Interactions across Tritrophic Levels: Legume Host Plants, Insect Pest Callosobruchus maculatus, and Parasitoid Dinarmus basalis

doi:10.21203/rs.3.rs-4880865/v1

Download PDF

Research Article

Interactions across Tritrophic Levels: Legume Host Plants, Insect Pest Callosobruchus maculatus, and Parasitoid Dinarmus basalis

https://doi.org/10.21203/rs.3.rs-4880865/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

In an attempt to explore the tritrophic interactions among legume host plants and an insect pest C. maculatus, and an insect parasitoid D. basalis were used in this study. C. maculatus strains favoring seeds rich in protein and carbohydrate exhibit optimal physical performance in terms of weight and size, as well as biological parameters such as longevity, adult emergence and fertility. Additionally, fecundity and egg fertility of C. maculatus females correlate with larval protein and carbohydrate intake, as well as food quality. Parasitoids, crucial for controlling host densities, rely on substantial protein, lipid, and carbohydrate intake for survival and reproductive success. Focused on correlation between life history parameters of adult’s parasitoids and the host biochemical composition. Larvae L4 sugar content significantly affects parasitoid adults, with a notable positive relationship between sugar content in C. maculatus larvae and D. basalis sex ratio. This study is the first to investigate the relationships between the biochemical composition of C. maculatus L4 larvae and the biological and demographic performances of its parasitoid D. basalis. Our results show that the macronutrient content of plants and pest plays a crucial role in determining the tritrophic interactions.

Tritrophic interactions

Legume Host Plants

Insect Pests

Callosobruchus maculatus

Parasitoids

Dinarmus basalis.

In order to implement effective insect pest management practices, it is essential to understand the species richness and diversity of parasitoids, as well as how they interact (Heraty 2017). Parasites have negative effects on their hosts both individually and population-wise. As such, they can be used against insect’s pests. Biological control methods against crop pests are based on this principle. An ecosystem can be protected or reduced by utilizing naturally occurring living organisms in the ecosystem (Wajnberg and Ris 2007). The majority of beneficial organisms are parasitic insects, which represent more than a hundred species worldwide (Heraty 2017). Parasitic insects develop at the expense of another organism, their host. The quality of the host directly affects the development and survival of the parasitic insect. Therefore, the number of offspring produced by female insects depends on their ability to locate and determine the quality of their hosts (Lebreton et al. 2009). Parasitic insects reproduce by laying their eggs on other insect hosts. These hosts then become the only source of nutrition available for the development of the larvae. Therefore, the quality of the host directly influences the success of the development of the parasitic larvae (Godfray 1994). Interactions between hosts and parasites are omnipresent in ecosystems and are widely recognized as important factors driving dynamic evolutionary change (Hovestadt et al. 2019). Female parasitoid insects typically search their environment for suitable hosts, which are usually other insects, in order to lay their eggs. In many species, females also need to feed on the host to obtain the necessary nutrients for egg development and production (Giron et al. 2002).

A significant motivation for this study is to broaden our understanding of tritrophic interactions. Although, tritrophic interactions have been widely speculated upon, studies have typically focused on whole trophic levels or have been limited to specific taxonomic groups (Tong-Xian 2009). The majority of species-level studies have focused on the interactions among a plant, an insect herbivore, and an insect predator or parasitoid (Greenberg et al. 2009). Host plant-parasitic plant-herbivore interactions provide a unique system for studying interactions among three trophic levels (Havill and Raffa 2000). While it has been hypothesized that these interactions are similar to those observed in plant-insect herbivore-parasitoid interactions, relatively little research has been done to compare interaction patterns in these two systems (De Moraes et al. 2000).

Dinarmus basalis (Rondani, 1877) (Hymenoptera: Pteromalidae) is the most commonly used ectoparasitic insect in biological control of the cowpea weevil, Callosobruchus maculatus (Fabricius, 1775) (Coleoptera: Chrysomelidae) (Ouedraogo et al. 1996; Ketoh et al. 2002; Fung et al. 2023). This parasitoid is effective against the fourth stage larvae and nymphs of its host. The use of D. basalis appears to be a good alternative and allows for a significant reduction in the populations of C. maculatus (Akinbuluma and Chinaka 2023). It has been emphasized in biological control programs that natural enemies interact with their hosts. Although, the effects of host plants on biocontrol programs must be considered, recent decades have seen an increase in the use of tritrophic interactions between plants, herbivores, and natural enemies for biological control (Rashedi et al. 2019). No research has been conducted to investigate the interactions between legume, and their parasite the cowpea weevil, C. maculatus, as well as their parasitoid D. basalis.

Hence, in an attempt to explore the tritrophic interactions among: (i) two plants the chickpea (Cicer arietinum L.) and the cowpea (Vigna unguiculata L.), (ii) an insect herbivore, the cowpea weevil (Callosobruchus maculatus), and (iii) an insect parasitoid Dinarmus basalis were used in this study. Tritrophic interactions were evaluated by understanding the biological and demographic performances of female D. basalis with alimentation availability and strains in order to exploit their parasitic potential against C. maculatus during storage. Furthermore, through this study, we aimed to investigate the relationships between the biochemical composition of C. maculatus L4 larvae and the biological and demographic performances of its parasitoid D. basalis.

Plants hosts

Three food legumes hosts were used a cowpea (Vigna unguiculata L.), two Kabuli type chickpea (Cicer arietinum) varieties namely Amdoun 1 (Pedigree Be-sel-81-48) and Beja 1 (Pedigree INRAT 93 − 1). This legumes hosts provided by the national chickpea improvement program germplasm collection. Plants belongs to the same family (Leguminosae, Fabaceae) nevertheless they differ in their defensive chemistry. These legumes hosts served as food substrates for the insect rearing.

Experimental conditions and insect rearing

Two strains of C. maculatus originated, since 2011, from the Laboratory of Biotechnology Applied to Agriculture at The National Agricultural Research Institute of Tunisia (INRAT). The insects were reared on the chickpea (C. arietinum L.) (SC = C. maculatus strain rearing on chickpea C. arietinum) and the cowpea (V. unguiculata L.) (SV = C. maculatus strain rearing on cowpea V. unguiculata) for at least ninety generations under laboratory conditions at 30 ± 2°C, relative humidity of 65 ± 5% and a photoperiod of 12L: 12D. Additionally, a wild colony of C. maculatus collected from infested chickpea provided by the Field Crops' (WS = wild strain of C. maculatus feeding on chickpea C. arietinum (Beja 1).

Whole host body of fourth instar (l4) larvae extracts

The whole host body extracts from the three C. maculatus strains were analysed individually. In effect, the quantification of the lipid, sugar, glycogen and protein from the fourth instar (L4) larvae was determined according Haouel-Hamdi et al. (2021).

Reproductive parameters and demographic traits of Callosobruchus maculatus and Dinarmus basalis

The reproductive parameters and demographic traits of C. maculatus such as the longevity of adults (male and female), the total number of eggs laid, the fertility rate, corporal performance, the immature development period and the emergence rate were determined using the methods of Haouel-Hamdi et al. (2017). Furthermore, the longevity of adults, the immature development period, the mean growth rate and sex ratio of D. basalis were analysed based on methods of Haouel-Hamdi et al. (2021). In addition, the mass rearing method of D. basalis colony used on the three C. maculatus strains has been described by Haouel-Hamdi (2021) and Den Hollander (2009).

Statistical analysis

Data analysis were performed using SPSS statistical software version 20.0 (IBM Corporation, New York, USA) and R® program, Version 4.3.0 and the integrated development environment RStudio v1.2.1335. All values given were the mean of three replications and were expressed as the mean ± SD. For each performances and the reproductive parameters and demographic traits, data were subjected to two-way ANOVA. The means were separated using the Least Significant Difference (LSD) (P < 0.05). Differences in values of each variety to the food supply or seed category were tested by one-way ANOVA followed by Duncan and SNK test. Where necessary, data were transformed by common logarithm or square root to meet the assumptions of normality. All values given were the mean of three replications and were expressed as the mean standard deviation (SD). Significant differences are reported as P < 0.05. Correlations analyses (Pearson's correlation coefficient) were established between variables retained for tritrophic interactions modeling. Person’s rank correlation was calculated in R® program, using the function “ggcorr”. Plots such as Geom-violin plot and linear regression were created using the ggplot2 and the Corrplot pakage (package in R program).

Physico-chemical characteristics of plants

Tables 1 summarize results of the impact of strains and on proximate composition such as crude fat, ash, protein content, moisture, carbohydrate and caloric value of infested and unifested seeds by C. maculatus reared on two chickpea varieties and cowpea. Results revealed that proximate composition changes in the seeds infested by C. maculatus were recorded. These results indicate marginal elevations in crude protein and moisture content in the infested samples. Conversely, there were minor reductions in crude fat, ash, carbohydrate content and caloric value due to infestation. The variations in nutrient values were determined to be statistically significant with a P-value less than 0.05. The proximate composition was significantly significantly affected by seed variety. All studied parameters as protein (F_1,12 = 57.27, p ≤ 0.001), moisture (F_1,12 = 31.53, p ≤ 0.001), ash contents (F_1,12 = 30.81, p ≤ 0.001), crude fat (F_1,12 = 72.49, p ≤ 0.001), carbohydrate (F_1,12 = 46.59, p ≤ 0.001) and nutritional values (F_1,12 = 1150.54, p ≤ 0.001) were also affected by the interaction between variety and seed infestation.

Table 1

Effect of strains and on proximate composition (crude fat (%), ash (%), protein content (%), moisture (%) and carbohydrate (%)) and caloric value (Kcal) of infested and unifested seeds
	Uninfested			Infested
	C. arietinum		V. unguiculata	C. arietinum		V. unguiculata
	SC	WS	SV	SC	WS	SV
Crude fat	4.91 ± 0.07^b,B	4.73 ± 0.15^b,B	3.67 ± 0.51^a,B	3.28 ± 0.19^b,A	3.54 ± 0.25^b,A	2.33 ± 0.58^a,A
Ash	3.44 ± 0.09^a,A	3.36 ± 0.11^a,A	4.26 ± 0.15^b,B	4.06 ± 0.25^a,B	4.64 ± 0.15^b,B	3.71 ± 0.22^a,A
Protein	21.81 ± 0.57^a,A	22.53 ± 0.93^a,A	24.69 ± 1.01^b,A	23.77 ± 0.14^a,B	33.05 ± 0.62^c,B	26.46 ± 0.59^b,A
Moisture	10.65 ± 0.17^b,A	10.67 ± 0.26^b,A	9.56 ± 0.17^a,B	12.72 ± 0.32^c,B	10.80 ± 0.20^b,A	9.11 ± 0.16^a,A
Carbohydrate	59.19 ± 0.53^b,A	58.70 ± 0.85^b,B	84.79 ± 4.01^a,B	59.16 ± 0.05^c,A	47.96 ± 0.58^b,A	44.68 ± 1.22^a,A
Caloric value	368.23 ± 1.29^a,B	367.51 ± 1.41^a,B	369.53 ± 0.91^a,B	349.30 ± 1.22^b,A	355.91 ± 1.57^c,A	341.67 ± 0.67^a,A
SC = C. maculatus strain rearing on chickpea Cicer arietinum (Amdoun 1), SV = C. maculatus strain rearing on cowpea V. unguiculata and WS = wild strain of C. maculatus feeding on chickpea Cicer arietinum (Beja 1). Means ± SD. Different letters denote significant differences between strains (P < 0.05, lowercase). Uppercase letters denote significant differences in longevity between honey availability (* P < 0.05, uppercase).

Longevity of Callosobruchus maculatus adults

Figure 1 summarizes results of the influence of seed availability (present and absent seeds) and adults mating (mated or no mated) on longevity of C. maculatus adults males and females of three strains (strain rearing on chickpea, strain rearing on cowpea and wild strain). Results showed that longevity was affected by seed availability (F_1,18 = 106.97, p ≤ 0.001), mating (F_1,18 = 114.35, p ≤ 0.001), strain (F_2,18 = 99.02, p ≤ 0.001) and sex (F_1,18 = 21.97, p ≤ 0.001). Furthermore, results revealed that the seed availability and mating increases the adults longevity of C. maculatus in both sex males and females. In addition, there was a significant interaction between seed availability and mating (F_1,18 = 13.86, p = 0.001). This was maybe due to the large difference in offspring production between bioessais (Fig. 1). Thus, the presence of seeds negatively affects female longevity. Lifespan results showed maximum longevity of 18 days that was observed in unmated females of the cowpea strain without food resources. On the other hand, the minimum lifespan was 6 days recorded through unmated males with food resources in the cowpea strain and mated males with the chickpea strain without food resources.

Linear regression model

Figure 2 illustrated the body size and body weight of C. maculatus males and females adults of three strains according to linear regression line plotted. Linear regression analysis revealed that hosts have significant effects on adults performance (body weight, body size) (SV: R² = 0.464; SC: R² = 0.714; WS: R² = 0.706;) confirming results of correlation analysis. A regression analysis between the weight of C. maculatus as a dependent variable and the size as an independent variable indicated a highly significant positive correlation between these variables (Fig. 2). The results showed that the size of C. maculatus increases when weights increase. Results related to the prediction of the relationship between these two parameters according to linear models showed that adult’s performance (body weight and size) was more performed with the adults of wild strain (WS) and the adults reared on cowpea (SC).

The results demonstrated the importance of the host for explaining significant portions of the independent variable for fitness of C. maculatus. An examination of the host contribution to adult fitness could be accomplished through a linear regression analysis. Furthermore, according to a linear regression analysis, sex has a significant effect on fitness in adults (body weight, body size) (F = 56.19, P ≤ 0.001, R² = 0.52, Fig. 2). C. maculatus fitness is also influenced by the sex, which explains significant portions of the independent variable. As a result of the linear regression analysis, it was possible to investigate the role of sex in the variation of adults' fitness. Results indicated that the sex contributed respectively by 52% for variation in adults' fitness.

Reproductive parameters and demographic traits of Callosobruchus maculatus

The reproductive parameters and demographic parameters of C. maculatus reared on three legumes hosts chickpea and cowpea were showed in Fig. 3. Results revealed that the host legumes affect significantly all demographic parameters such as fertility rate, emergence rate, mortality rate of larvae and mean growth rate of C. maculatus. The finding indicated that the reproductive parameters of C. maculatus differed according host legumes. Results showed that fertility rate varied according to the strain. In fact, best performance were recorded when insect was reared on cowpea. However, the wild crops strain recorded the lowest number of fertile eggs, with averages of logfertile 4.48 eggs/female. Furthermore, statistical differences were detected between the three hosts regarding fertility parameter (F_2,8 = 20.61, P = 0.002).

Demographic traits data revealed that C. maculatus performances were dependent on host legumes (mortality rate of larvae: F_2,8 = 8.29, P = 0.02; emergence rate: F_2,8 = 10.83, P = 0.01; mean growth rate: F_2,8 = 10.72, P = 0.01). Cowpea appeared as the most suitable host compared to chickpea. In fact, significant differences were obtained between emergence rate (51% with SV strain, 28.33% with SC strain an 22.67% with WS strain) and mean growth rate of strains (24.67% with SV strain, 13.33% with SC strain an 10.33% with WS strain). C. maculatus could successfully survive and reproduce both on cowpea and chickpea, with a food-preference tendency to cowpea and chickpea under laboratory condition.

Biochemical composition of whole body extract of Callosobruchus maculatus l4

The results of the study on the average composition of glycogens, sugars, lipids, and proteins (µg/µL) in the whole body extract of L4 larvae from the three strains of C. maculats were presented in the Fig. 4. The composition of whole body extracts differ widely in the amount of the biochemical constituents for the three strains (SC, SV and WS). Furthermore, there were no statistical differences in the amount of glycogens (F_2,38 = 1.24, P = 0.302) and proteins (F_2,38 = 2.04, P = 0.14) between C. maculatus strains. Results showed that the glycogens content reached 2.70, 3.04 and 3.19 µg/µL respectively for the cowpea strain, laboratory strain and wild strain. Indeed, protein content indicated a non significant variation between strains. This content varied from 13.14, 15.15 and 16.91 µg/µL respectively for laboratory strain, cowpea strain and wild strain.

In contrast, hole body extracts were widely different on the average composition of sugars and lipids between the three strains. ANOVA revealed significant effects of C. maculatus strains on the amount the biochemical constituents such as sugar (F_2,38 = 7.38, P = 0.002) and lipids F_2,38 = 7.41, P = 0.002). Concerning sugar content, the cowpea strain recorded the highest content with a value of 19.99 µg/µL compared to 13.66 and 14.88 µg/µL respectively for laboratory strain and wild strain. On the other hand, the wild strain exhibited the highest lipid content with a value of 9.15 µg/µL compared to 8.82 and 8.83 µg/µL respectively for laboratory strain and cowpea strain.

Longevity of Dinarmus basalis adults

D. basalis adult’s males and females longevity of three strains and host availability (present and absent of C. maculatus L4) were illustrated in Fig. 5. The longevity of male and female adults varies depending on sex and strain. Indeed, the lifespan of female individuals were significantly higher than males. Results showed that longevity of D. basalis adult’s was affected by host availability (F_3,72 = 3.51, p = 0.02). Additionally, adult’s longevity was influenced by adult’s sex (F_1,72 = 8.59, p ≤ 0.005). Nonetheless, there was no significant interaction between host availability and sex (F_3,72 = 0.42, p = 0.74). Furthermore, results revealed that the host availability decreases the adult’s longevity of D. basalis in both sex males and females. Overall, the adult’s longevity of D. basalis varied between 7.11 and 9.56 days. Lifespan results showed maximum longevity of 9.56 days that was observed with D. basalis females feeds on L4 of the cowpea strain. On the other hand, the minimum lifespan was 7.11 days recorded through D. basalis males without food resources.

Reproductive parameters and demographic traits of Dinarmus basalis

Tables 2 summarize results of the impact of three strains of C. maculatus reared on two chickpea varieties (Amdoun 1 and Beja 1) and cowpea on reproductive parameters. Results showed that development period, parasitism rate, emergence rate and mean growth rate were affected by strains (development period: F_2,36 = 25.00, p = ≤ 0.001; parasitism rate: F_2,36 = 14.92, p ≤ 0.001; emergence rate: F_2,36 = 14.88, p ≤ 0.001; mean growth rate: F_2,36 = 11.96, p ≤ 0.001; Sex-ratio: F_2,36 = 6.47, p = 0.007). Additionally, results showed that wild strain significantly offered better performances for D. basalis adults in terms of the development period (17.50 days with wild strain against 16.50 days for chickpea SC and cowpea SV strain respectively), parasitism rate (96.66%, 68.89% and 55.55% with wild strain, chickpea and cowpea strain respectively), emergence rate (14.50%, 10.33% and 8.33% with wild strain, chickpea and cowpea strain respectively) and mean growth rate (3.25% and 2.17% with wild WS and chickpea SC strain respectively against only 0.83% for cowpea SV strain).

Table 2

Effect of strains on reproductive parameters of *Dinarmus basalis* development period (days), parasitism rate (%), emergence rate (%), mean growth rate (%) and Sex-ratio.
Strain	DP^‡	PR^‡	ER^‡	MGR^‡	SR^‡
SV	16.50 ± 1.64 ^a	55.55 ± 19.01 ^a	8.33 ± 2.85 ^a	0.83 ± 0.81 ^a	0.78 ± 0.02 ^b
SC	16.50 ± 0.00 ^a	68.89 ± 21.17 ^b	10.33 ± 3.18 ^b	2.17 ± 0.89 ^b	0.59 ± 0.03 ^a
WS	17.50 ± 0.58 ^b	96.66 ± 0.00 ^c	14.50 ± 0.00 ^c	3.25 ± 0.00 ^b	0.54 ± 0.04 ^a
^‡ DP = Development Period, PR = Parasitism rate, ER = Emergence rate, MGR = mean growth rate, SC = C. maculatus strain rearing on chickpea C. arietinum, SV = C. maculatus strain rearing on cowpea V. unguiculata and WS = wild strain of C. maculatus, Different letters denote significant differences between strains (P < 0.05, lowercase). Uppercase letters denote significant differences in longevity between host availability (P < 0.05, uppercase).

Correlations analysis

The relationship between variables retained for tritrophic interactions modeling was analyzed using Pearson correlation coefficients (Fig. 6). Corrplot analyses were conducted in the combination of all the data including the physico-chemical characteristics of legume plants, the reproductive parameters of C. maculatus and D. basalis and quantification in whole host body extract of forth larvae of C. maculatus. Only Pearson’s correlation values that were significant (p-value < 0.05 expressed by one star) and highly significant (p-value ≤ 0.001 expressed by two star) were showed in the plot. Correlations analyses providing insights into the linear associations and underlying structures of the data.

In order to understand how legume seeds interact with population growth parameters of C. maculatus, some biochemical and physical characteristics were measured. As a result of feeding on various legume seeds, C. maculatus showed significantly different biological properties. In addition, correlation analysis between the characteristics of legume plants hosts and the C. maculatus performance demonstrated that the body weight and size of the beetle C. maculatus was correlated with fat (weight: r = 0.373^**; size: r = 0.615^**), moisture (weight: r = 0.533^**; size: r = 0.614^**), carbohydrate (weight: r = 0.549^**; size: r = 0.579^**) and protein content (weight: r = -0.463^**; size: r = − 0.564^**). In fact, the results showed that C. maculatus population associates a benefit in terms of weight and size with feeding on legume seeds rich on fat, moisture and carbohydrate.

Correlation analyses exploited population variation in biological parameters of the C. maculatus to determine if one benefit associated with feeding on various hosts accelerated means growth rate. Furthermore, results showed that significantly offered better performances for adults in terms of longevity (longevity and weight r = 0.272^*). Therefore, fertility rate of C. maculatus adults was correlated with protein content in seeds (r = 0.588^**), moisture content in seeds (r = -0.897^**), carbohydrate in seeds (r= -0.920^**). Positive correlation was recorded between emergence rate and moisture content in seeds (r = 0.815^**) and carbohydrate (r = 0.870^**). Furthermore, mortality rate of larvae was correlated with protein content (r = 0.729^**), MRL and fat (r = − 0.610^**), MRL and moisture (r = − 0.711^**). A highly positive correlation was recorded between the mean growth rate and fat (r = 0.608^**), the mean growth rate and moisture (r = 0.586^**), the mean growth rate and carboydrate (r = 0.588^**) and the mean growth rate with weight (r = 0.500^**) and with size (r = 0.532^**). These results pointed out the direct effect of legume host on adults’ fitness and performance.

In order to explore relationships between the physico-chemical characteristics of legume plants hosts and composition of whole host body extract of forth larvae of C. maculatus in a data set Pearson’s correlation were conducted. Results showed that the correlation coefficients taken 2 to 2 at the 0.01% threshold are very strong and mostly positive. Significant and positive correlation was observed between content in legume plants and content in body extract of C. maculatus L4 respectively caloric value (seed) and glycogen (L4) (r = 0.278^*). Two positive correlation were saved with moisture content in seeds and sugar content in L4 (r = 0.364^**) and between carbohydrate (seed) and lipid (L4) (r = 0.445^**). However, a negative correlation was recorded between protein content in seeds and sugar content in L4 (r = -0.483^**). In the other hand, larvae that feed on seeds rich in fat have poor protein levels (r = − 0.268^*) and lipid levels (r = − 0.608^**).

Furthermore, to determine the effect of biochemical nature of C. maculatus strains on reproductive parameters and demographic traits of D. basalis correlations analyses were performed (Fig. 6). Therefore, weight of C. maculatus larvae was correlated D. basalis longevity (r = 0.416^**), sex ratio (r = 0.462^**), parasitism rate (r = − 0.391^**) and means growth rate (r = − 0.256^**). The content of sugar, lipid and protein content in the C. maculatus L4 significantly affected the reproductive and demographic parameters. Further, the relative proportion of lipids varied significantly and a positive high correlation were recorded with parasitism rate (r = 0.518^**), means growth rate (r = 0.567^**) and with development period (r = 0.590^**). Moreover, the protein content correlated only with parasitism rate (r = 0.258^*). Furthermore, sugar content in C. maculatus forth larvae was correlated with D. basalis adults longevity (r = 0.532^**) and sex ratio (r = 534^**). Nevertheless, no correlation was observed with glycogen content. It appears that larval chemical compositions of larvae L4 had a significant impact on reproductive parameters and demographic characteristics of D. basalis. Therefore, when C. maculatus fourth larvae are heavier, D. basalis performance increases. In general, parasitism rate increased with host size, resulting in higher longevity, mean growth rate, and parasitism rate. D. basalis females can advance in fitness by increasing longevity, mean growth rate, and parasitism rate.

D. basalis longevity was positively correlated with C. maculatus emergence rate (r = 0.683^**) and C. maculatus mean growth rate (r = 0.683^**) but had a significantly negative correlation with C. maculatus fecundity rate (r = − 0.796^**). In fact, the D. basalis parasitism rate were significantly positively correlated with C. maculatus larvae mortality rate (r = 0.590^**) and D. basalis adults longevity (r = 0.427^**). Furthermore, the D. basalis mean growth rate had a positive correlation with C. maculatus fecundity (r = 0.317^*) and with C. maculatus larvae mortality (r = 0.688^**), and had a negative correlation with C. maculatus emergence rate (r = − 0.383^**) and with the C. maculatus mean growth rate (r = − 0.383^**). Additionally, the D. basalis mean growth rate had a positive correlation with parasitism rate (r = 0.977^**) and development period (r = 0.953^**).

This study reveals that females of the D. basalis species not only improve their fitness by increasing longevity but also through an enhanced growth rate and lowered parasitism rate. According to our results, a general ascertainment demonstrated that increase in the host size and weight was accompanied with an increase in parasitism rate and D. basalis parasitoid performance. Parasitism rates and sex ratios skewed in favour of females when heavy host bodies were present. Furthermore, D. basalis adults that feed heavily on heavy host bodies exhibit an extended lifespan. In addition, the study emphasizes that being a small host does not hinder D. basalis from achieving commendable performances. This study illustrates that D. basalis effectively controls and reduces C. maculatus populations, achieving a parasitism rate as high as 86%.

In this report, we present the first results of the tritrophic interactions study among legume host plants, insect pest Callosobruchus maculatus, and parasitoids Dinarmus basalis. Plant-insect Interactions theory have focused almost entirely on relationship between plants and insect, with little attention to tritrophic interactions plant-insect-parasitoid.

Based on our observations of the changing biological parameters of C. maculatus on various host-plants, we hypothesized that the nutritional value of the food-plant could be the predominant factor influencing the C. maculatus. The seeds of plants have rich reserves of proteins, carbohydrates and lipids as valuable food sources. Moreover, seeds were critical components of fitness for most plants and thus can be among the most highly defended plant organs (Zangerl and Bazzaz 1992). Additionally, seeds contain rich nutritional resources habitually existing in concentrated form to reduce seed size and weight (Janzen 1971). According Karasov et al. (2011) and Borzoui et al. (2017) the life cycle traits of animals can be significantly influenced by the quality and quantity of their food supply, as they derive energy and nutrients from their food. These factors play a pivotal role in determining various aspects of their life cycle. Previous studies have demonstrated that the growth and development of C. maculatus are affected by the nutritional value and size of seeds (van Huis and De Rooy 1998), the age and body weight of the female (Fox 1993), population density (Kazemi et al. 2009), larvae competition (Messina and Slade 1999), and the strain of C. maculatus (Soumaya Haouel-Hamdi et al. 2017). Our results confirmed this hypothesis. In fact, our data revealed that C. maculatus exhibited more significant development on plants rich in fat and moisture, while its development was less pronounced on plants rich in protein. The study conducted by Borzoui et al. (2017) revealed that the energy reserves, encompassing total protein, glycogen, and lipid content, hold significant importance in shaping the fitness attributes of an insect individual, such as its development and fecundity. Differences in the macronutrient content of plants such protein, carbohydrate, fat, fiber and energy can be observed both within and between species, owing to variations in their genetic characteristics and the prevailing environmental conditions (Le Gall and Behmer 2014; Ehsan Borzoui et al. 2015). The findings from our study clearly indicate that strains feeding on seeds rich in protein and carbohydrate, leading to optimal physical performance in terms of weight and size, as well as biological parameters such as longevity, adult emergence and fertility. Furthermore, the fecundity and egg fertility of C. maculatus females was influenced by the amount of protein and carbohydrate consumed and digested by larvae, as well as the quality of their food. Our own research consistent with those of Borzoui et al. (2015) Mebarkia et al. (2010), as were observed that the fecundity and fertility of Trogoderma granarium (Ehsan Borzoui et al. 2015) and Sitophilus granaries (Mebarkia et al. 2010) were significantly impacted by different host diets tested. Indeed, the process of natural selection favors phytophagous insects that possess the ability to regulate their nutrient intake in a balanced manner (Behmer 2009). This equilibrium is dependent on the intricate interplay between the consumption of food, the process of digestion, and the allocation of acquired energy towards various biological functions such as growth, survival, and reproduction (Naya et al. 2007).

Furthermore, reduction of life span as a result of mating in the cowpea beetle C. maculatus was reported by den Hollander et al. (2009). Furthermore, decline longevity was described also in other species in the alfalfa leaf cutting bee, Megachile rotundata (Rossi et al. 2010). In contrast, the study of Kotiaho et al. (2003) demonstrated that with the dung beetle Onthophagus binodis there was a longevity cost of reproduction for males but no longevity cost of mating or courtship for females. Although, Huang et al. (2005) confirmed that females show no decrease in lifetime fecundity when host availability time is limited to only 4 h on each day. However, longevity significantly increases when the female is provided with small beans after host deprivation. Additionally, Fox and Tatar (1994) demonstrated that manipulation of host availability affects the lifespan of virgin beetles, deprived females may live longer because of decreasing contact with hosts. Previous research of Lynch and Ennis (1983) has revealed that the nutritional conditions of maternal environment play a major role in determining the progeny’s phenotype

Earlier studies have indicated that parasitoids offer exceptional opportunities for testing hypotheses concerning the evolution of behavior and life-history strategies (Giron et al. 2002). Indeed, parasitoids females actively search their surrounding for potential hosts, usually other insects, in which they can lay their eggs (Heimpel and Collier 1997). Phenological, behavioural or physiological limitations may prevent the use of certain hosts, with behavioural adaptations often preceding physiological adaptations in the evolution of host specificity (Futuyma and Moreno 1988). Nevertheless, few studies focused on correlation between host densities, life history parameters of adult’s parasitoids and the host biochemical composition. In fact, parasitoids required substantial quantities of protein, lipid and carbohydrate to ensure their survival and reproductive success. Our research focused on investigating the impact of host quality (biochemical composition) on the biological parameters of parasitoid D. basalis. Previous research of Giron et al. (2002) have examined the impact of diverse adult diets on fecundity and longevity. The finding from our study clearly indicate that the sugar in Larvae L4 have significant effect on parasitoid adults. In compatible with the finding of Giron et al. (2002) and Olson et al. (2000), we found that sugar have a critical effect on longevity of most parasitoids tests so far. Furthermore, the impact of specific sugars in determining parasitoids longevity directly or indirectly (Olson et al. 2000). Furthermore, the primary energy source utilized by adult parasitoids is sugar (Wäckers et al. 2006)^, (Lee et al. 2006). Studies of Kidd and Jervis (1989) have reported that foods high in sugar play a crucial role in sustaining female insects in the early phase of adult life, with certain species actively seeking out sugar-rich sources in their natural habitats.

Our finding demonstrated that a highly significant positive relationship was observed between sugar content in C. maculatus larvae and D. basalis sex ratio. It can be inferred that when the host of D. basalis is rich in sugars, the female produces offspring biased towards females. The work of Thomas et al. (2007) confirmed our findings and confirmed that the female chooses to fertilize or not her egg based on the size of the host or the extent of reserves. Generally, if the larva's food is ample, the female lays a fertilized egg that will yield a female; however, if the quantity is insufficient, she lays an unfertilized egg that will produce a fertile male. This behavior thus influences the sex ratio (Lécureuil et al. 2012). Thus, when the host of D. basalis is high in sugars the female gives offspring in favor of females. The results also revealed the importance of protein and lipid contents on the increase of the rate of parasitism.

Overall, the above findings suggest that wasps had access to more than one host, however, produce more progeny to the next generation. This is an important consideration in the utilization of biological control agents. This situation suggest that newly emerged adults have to loaded with a certain amounts of nutrients such as protein, glycogen, sugar and lipid to sustain egg production and metabolic needs.

Conflicts of interest

The authors declare no conflicts of interest.

Informed consent

Informed consent was obtained from all individual participants included in the study.

ORCID

Soumaya Haouel-Hamdi http://orcid.org/0000-0002-2689-8424

Acknowledgement

The authors wish to thank Dr. Mariam Hedjal-Chebheb from Faculty of Biologic and Agronomic Sciences, University Mouloud Mammeri, Tizi-Ouzou, Algeria she provided us with cowpea seeds.

Akinbuluma MD, Chinaka OP (2023) Efficacy of the parasitic wasp, Dinarmus basalis Rondani (Hymenoptera: Pteromalidae), in reducing infestations by the cowpea beetle, Callosobruchus maculatus (L.)(Coleoptera: Chrysomelidae: Bruchinae). Egypt J Biol Pest Control 33(1):43
Behmer ST (2009) Insect herbivore nutrient regulation. Ann Rev Entomol 54:165–187
Borzoui E, Naseri B, Namin FR (2015) Different diets affecting biology and digestive physiology of the Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae). J Stored Prod Res 62:1–7
Borzoui E, Naseri B, Nouri-Ganbalani G (2017) Effects of food quality on biology and physiological traits of Sitotroga cerealella (Lepidoptera: Gelechiidae). J Econ Entomol 110(1):266–273
De Moraes CM, Lewis W, Tumlinson JH (2000) Examining plant-parasitoid interactions in tritrophic systems. Anais da Sociedade Entomológica do Brasil 29:189–203
Den Hollander M, Gwynne DT (2009) Female fitness consequences of male harassment and copulation in seed beetles, Callosobruchus maculatus. Anim Behav 78(5):1061–1070
Fox CW (1993) The influence of maternal age and mating frequency on egg size and offspring performance in Callosobruchus maculatus (Coleoptera: Bruchidae). Oecologia 96:139–146
Fox CW, Tatar M (1994) Oviposition substrate affects adult mortality, independent of reproduction, in the seed beetle Callosobruchus maculatus. Ecol Entomol 19(2):108–110
Fung C, Asante K, Fellowes MD, González-Suárez M (2023) Ectoparasitoid Dinarmus basalis causes greater offspring loss to the winged morph of Callosobruchus maculatus. J Stored Prod Res 103:102147
Futuyma DJ, Moreno G (1988) The evolution of ecological specialization. Annu Rev Ecol Syst 19(1):207–233
Giron D, Rivero A, Mandon N, Darrouzet E, Casas J (2002) The physiology of host feeding in parasitic wasps: implications for survival. Funct Ecol 16(6):750–757
Godfray HCJ (1994) Parasitoids: behavioral and evolutionary ecology, vol 67. Princeton University Press
Greenberg SM, Jones WA, Liu T-X (2009) Tritrophic interactions among host plants, whiteflies, and parasitoids. Southwest Entomol 34(4):431–445
Haouel-Hamdi S, Ferchcichi M, Hedjal-Chebheb M, Boushih E, Mediouni-Ben Jemâa J (2021) (pp Dynamics of parasitoid-host interac-tion: Application of the case of Callosobruchus maculatus (Chrysomelidae) and Dinarmus basalis (Pteromalidae). In Proceedings of the 1st Interna-tional Electronic Conference on En-tomology, 1–15)
Haouel-Hamdi S, Titouhi F, Boushih E, Dhraief M, Amri M, Mediouni Ben Jemâa J (2017) Population demographic and reproductive parameters of the cowpea seed beetle Callosobruchus maculatus infesting stored lentil and chickpea commodities. Tunisian J Plant Prot 12(1):67–81
Havill NP, Raffa KF (2000) Compound effects of induced plant responses on insect herbivores and parasitoids: implications for tritrophic interactions. Ecol Entomol 25(2):171–179
Heimpel GE, Collier TR (1997) The evolution of host-feeding behaviour in insect parasitoids
Heraty J (2017) Parasitoid biodiversity and insect pest management. Insect biodiversity: science and society: 603–625
Hovestadt T, Thomas JA, Mitesser O, Schönrogge K (2019) Multiple host use and the dynamics of host switching in host–parasite systems. Insect Conserv Divers 12(6):511–522
Huang CC, Yang RL, Lee HJ, Horng SB (2005) Beyond fecundity and longevity: trade-offs between reproduction and survival mediated by behavioural responses of the seed beetle, Callosobruchus maculatus. Physiol Entomol 30(4):381–387
Janzen DH (1971) Seed predation by animals. Annu Rev Ecol Syst 2(1):465–492
Karasov WH, del Martinez C, Caviedes-Vidal E (2011) Ecological physiology of diet and digestive systems. Annu Rev Physiol 73:69–93
Kazemi F, Talebi AA, Fathipour Y, Farahani S (2009) A comparative study on the effect of four leguminous species on biological and population growth parameters of Callosobruchus maculatus (F.)(Col.: Bruchidae). Adv Environ Biology 3(3):226–232
Ketoh GK, Glitho AI, Huignard J (2002) Susceptibility of the bruchid Callosobruchus maculatus (Coleoptera: Bruchidae) and its parasitoid Dinarmus basalis (Hymenoptera: Pteromalidae) to three essential oils. J Econ Entomol 95(1):174–182
Kidd N, Jervis M (1989) The effects of host-feeding behaviour on the dynamics of parasitoid-host interactions, and the implications for biological control. Researches Popul Ecol 31(2):235–274
Kotiaho JS, Simmons LW (2003) Longevity cost of reproduction for males but no longevity cost of mating or courtship for females in the male dimorphic dung beetle Onthophagus binodis. J Insect Physiol 49(9):817–822
Le Gall M, Behmer ST (2014) Effects of protein and carbohydrate on an insect herbivore: the vista from a fitness landscape. The Society for Integrative and Comparative Biology
Lebreton S, Labarussias M, Chevrier C, Darrouzet E (2009) Discrimination of the age of conspecific eggs by an ovipositing ectoparasitic wasp. Entomol Exp Appl 130(1):28–34
Lécureuil C, Rougière N, Nguyen TM, Bressac C, Chevrier C (2012) Les hyménoptères parasitoïdes-Des modèles pour l’étude de l’hypofertilité mâle. médecine/sciences 28(1):76–81
Lee JC, Andow DA, Heimpel GE (2006) Influence of floral resources on sugar feeding and nutrient dynamics of a parasitoid in the field. Ecol Entomol 31(5):470–480
Lynch M, Ennis R (1983) Resource availability, maternal effects, and longevity. Exp Gerontol 18(2):147–165
Mebarkia A, Rahbé Y, Guechi A, Bouras A, Makhlouf M (2010) Susceptibility of twelve soft wheat varieties (Triticum aestivum) to Sitophilus granarius (L.)(Coleoptera: Curculionidae). Agric Biology J North Am 1(4):571–578
Messina FJ, Slade AF (1999) Expression of a life-history trade‐off in a seed beetle depends on environmental context. Physiol Entomol 24(4):358–363
Naya DE, Lardies MA, Bozinovic F (2007) The effect of diet quality on physiological and life-history traits in the harvestman Pachylus paessleri. J Insect Physiol 53(2):132–138
Olson D, Fadamiro H, Lundgren JG, Heimpel GE (2000) Effects of sugar feeding on carbohydrate and lipid metabolism in a parasitoid wasp. Physiol Entomol 25(1):17–26
Ouedraogo P, Sou S, Sanon A, Monge J, Huignard J, Tran Be et al (1996) Influence of temperature and humidity on populations of Callosobruchus maculatus (Coleoptera: Bruchidae) and its parasitoid Dinarmus basalis (Pteromalidae) in two climatic zones of Burkina Faso. Bull Entomol Res 86(6):695–702
Rashedi A, Rajabpour A, Rasekh A, Zandi-Sohani N (2019) Interactions between host plant, Aphis fabae, and its natural enemies, Orius albidipennis and Lysiphlebus fabarum in a tritrophic system. J Asia Pac Entomol 22(3):847–852
Rossi BH, Nonacs P, Pitts-Singer TL (2010) Sexual harassment by males reduces female fecundity in the alfalfa leafcutting bee, Megachile rotundata. Anim Behav 79(1):165–171
Thomas F, Guégan J-F, Renaud F (2007) Ecologie et Evolution des systèmes parasités. De Boeck
Tong-Xian L (2009) Tritrophic Interactions Among Host Plants, Whiteflies, and Parasitoids
van Huis Ae M (1998) The effect of leguminous plant species on Callosobruchus maculatus (Coleoptera: Bruchidae) and its egg parasitoid Uscana lariophaga (Hymenoptera: Trichogrammatidae). Bulletin of entomological research 88(1): 93–99
Wäckers F, Lee J, Heimpel G, Winkler K, Wagenaar R (2006) Hymenopteran parasitoids synthesize'honeydew-specific'oligosaccharides. Functional Ecology: 790–798
Wajnberg É, Ris N (2007) In: Thomas F, Guégan JF, Renaud F (eds) Parasitisme et lutte biologique. Ecologie et evolution des systèmes parasités. De Boek université, Bruxelles, pp 257–299
Zangerl AR, Bazzaz FA (1992) Theory and pattern in plant defense allocation. Plant resistance to herbivores and pathogens: 363–391

Download PDF

Version 1

posted

You are reading this latest preprint version

Interactions across Tritrophic Levels: Legume Host Plants, Insect Pest Callosobruchus maculatus, and Parasitoid Dinarmus basalis

Status:

Version 1

Abstract

Figures

Introduction

Material and Methods

Plants hosts

Experimental conditions and insect rearing

Whole host body of fourth instar (l4) larvae extracts

Statistical analysis

Results

Physico-chemical characteristics of plants

Linear regression model

Correlations analysis

Discussion

Conclusions

Declarations

Conflicts of interest

ORCID

Acknowledgement

References

Status:

Version 1