Intraguild Predation Research Articles

Interactions Between Non-Native Western Mosquitofish and Native Bluegill Sunfish: Mesocosm Experiments.

Aquatic ecosystems are often negatively affected by invasive species. However, biotic resistance by native species, either by competition or predation, can reduce the impacts of invasions by non-native species. The Western Mosquitofish (Gambusia affinis) is one of the most impactful invasive species of freshwater fish and cause declines in native fish populations. Using two mesocosm experiments conducted in different years, we examined the ecological interactions between juveniles of the native fish, Bluegill Sunfish (Lepomis macrochirus), and adults of the invasive fish, G. affinis. We found evidence for interactions between L. macrochirus and G. affinis. However, interactions did not appear symmetric, with L. macrochirus generally more affected by intraspecific interactions than interspecific interactions whereas G. affinis was more affected by interspecific interactions than intraspecific interactions. The presence of either species of fish led to a decrease in the number of large zooplankton and a tendency for a decrease in the total number of zooplankton. Based on these results, native L. macrochirus appear to be able to reduce the ability of non-native G. affinis to establish or maintain populations through both competition and predation (i.e., acting as an intraguild predator). The consistency of our results across both experiments, with their different designs and their occurring in different years, gives weight to these conclusions. The reduction of or prevention of establishment of populations of invasive G. affinis would likely benefit the aquatic communities of ponds with fish, especially small-bodied native fish.

Spatiotemporal Dynamics of an Intraguild Predation Model with Intraspecies Competition

Different species in the environment compete with one another for shared resources and suitable habitats. As a result, it becomes crucial to identify the essential components involved in preserving biodiversity. This paper describes the emergence of a wide range of temporal and spatiotemporal dynamics of an intraguild predation (IGP) model with intraspecies competition and Holling type-II response function between the IG-prey and IG-predator. To explore the dynamics of the temporal model, we study the local stability of all the biologically feasible steady states, global stability of the interior steady state, and Hopf bifurcation. Performing partial rank correlation coefficient (PRCC) sensitivity analysis, we picked more sensitive parameters and plotted the stability regions in two-parameter spaces. The dynamics exhibited by the system can demonstrate some important hallmarks noticed in the environments, such as the existence and nonexistence of oscillatory behavior in the IGP model. The analytical formulations for the stability and bifurcation of the coexistence of the steady-state are not easy to obtain, but we have verified numerically that the limit cycle bifurcates from the coexistence of the steady-state and there eventually emerges a chaotic behavior through period-doubling bifurcations. By plotting the largest Lyapunov exponent (LLE), we have verified that the temporal system experiences chaotic behavior. It is demonstrated that in the case of a diffusive system, diffusion may cause the coexistence of the steady state, which is otherwise stable, to become unstable. Criteria for the occurrence of Turing instability connected to the IGP model are derived. Our numerical illustrations demonstrate that diffusion-driven instability develops different stationary patterns based on the different initial conditions and diffusion parameters. The spatiotemporal patterns are observed in the Turing, Hopf–Turing, and Hopf regions.

Response of indicator species to changes in food web and ocean dynamics of the Ross Sea, Antarctica

Abstract Most of the Ross Sea has been designated a marine protected area (MPA), proposed ‘to protect ecosystem structure and function’. To assess effectiveness, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) selected Adélie (Pygoscelis adeliae) and emperor (Aptenodytes forsteri) penguins, Weddell seals (Leptonychotes weddellii) and Antarctic toothfish (Dissostichus mawsoni) as ecosystem change ‘indicator species’. Stable for decades, penguin and seal populations increased during 1998–2018 to surpass historical levels, indicating that change in ecosystem structure and function is underway. We review historical impacts to population trends, decadal datasets of ocean climate and fishing pressure on toothfish. Statistical modelling for Adélie penguins and Weddell seals indicates that variability in climate factors and cumulative extraction of adult toothfish may explain these trends. These mesopredators, and adult toothfish, all prey heavily on Antarctic silverfish (Pleuragramma antarcticum). Toothfish removal may be altering intraguild predation dynamics, leading to competitive release of silverfish and contributing to penguin and seal population changes. Despite decades of ocean/weather change, increases in indicator species numbers around Ross Island only began once the toothfish fishery commenced. The rational-use, ecosystem-based viewpoint promoted by CCAMLR regarding toothfish management needs re-evaluation, including in the context of the Ross Sea Region MPA.

Intraguild Predation or Spatial Separation? The efficacy and Interactions of Two Natural Enemy Species for the Biological Control of Pear Psyllid (Cacopsylla pyri)

AbstractPear psyllid (Cacopsylla pyri) is a persistent pest to the pear industry; with an estimated cost of £5 million per annum in the UK alone. This phloem feeding insect is resistant to a large proportion of approved pesticides, necessitating the use of alternative control strategies. Many pear growers practice integrated pest management (IPM) of pear psyllid, focusing on maximizing natural enemy populations, whilst minimizing the use of agrochemical sprays. The anthocorid Anthocoris nemoralis and the European earwig Forficula auricularia are particularly effective at controlling pear psyllid populations during the summer months. Despite the effectiveness of both natural enemies, there is a lack of understanding on whether both species should be promoted together or separately, due to the risk of intraguild predation (IGP) or interference competition. Furthermore, abiotic factors including temperature may influence both behaviors, altering activity level and niche overlap. Although IGP and interference competition have been documented between multiple species of natural enemies neither have been studied between these two specific predators. Using microcosm experiments, olfactometer assays and survival analyses this study demonstrated whether A. nemoralis and F. auricularia can be used in synchrony to control pear psyllid. Results indicated that IGP is present; F. auricularia will consume A. nemoralis when predators are not spatially separate and in absence of psyllid prey. There was no evidence for interference competition, although both predators consumed more prey at higher temperatures. This confirms that pear growers can encourage both predators for the control of pear psyllid without losing predation efficacy.

Effects of Encarsia formosa (Hymenoptera: Aphelinidae) parasitism on the feeding preference and performance of the whitefly predator Serangium japonicum (Coleoptera: Coccinellidae)

The relationship among the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), its predator Serangium japonicum (Coleoptera: Coccinellidae), and its parasitoid Encarsia formosa (Hymenoptera: Aphelinidae) can be defined as intraguild predation (IGP). IGP represents an interaction that combines elements of both predation and competition between two species. In our previous study, predators (S. japonicum) often indirectly reduce the number of parasitoids (E. formosa) by consuming shared food resources, such as B. tabaci. To suppress whitefly outbreaks, a combination of parasitoids and predators is often released together using a mixed-species approach. However, the impact of the parasitic behavior of parasitoids on the feeding behavior of specific predators, such as S. japonicum, has not yet been well-studied. We conducted a laboratory study to examine how the parasitoid E. formosa affects the predation rates and performance of S. japonicum. Results indicate that S. japonicum shows a preference for non-parasitized whiteflies over parasitized ones, regardless of the availability of choices. Furthermore, we found a correlation between the preference for non-parasitized whiteflies and the duration of parasitization. As the developmental days of the parasitoid mummies increased, the food intake of the predatory group decreased significantly. Additionally, as the parasitoid mummy develops, S. japonicum spends more time exploring and probing the mummy before deciding whether to consume it. In summary, our study suggests that S. japonicum exhibits a significant preference for consuming non-parasitized whiteflies. Therefore, it is important to coordinate the release timing of S. japonicum and E. formosa in the biological control of B. tabaci.

Trophic cascades regulate arthropods density and plant damage across forest strata.

Research Highlight: Sivault, E., Kollross, J., Jorge, L., Finnie, S., Diez Mendez, D., Fernandez Garzon, S., Maraia, H., Lenc, J., Libra, M., Masashi, M., Nakaji, T., Nakamura, M., Sreekar, R., Sam, L., Abe, T., Weiss, M., & Sam, K. (2024). Insectivorous birds and bats outperform ants in the top-down regulation of arthropods across strata of a Japanese temperate forest. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.14146. Top-down predators exert strong effects on prey populations. Theoretical and empirical studies investigating the cascading effects of predators on biodiversity dynamics and ecosystem functionality have been central to advancing ecology and conservation biology. Yet, how intraguild predation and niche overlap drive the strength and direction of trophic cascades across forest strata is still barely understood. In a study published in this issue, Sivault etal. (2024) investigated the impacts of excluding vertebrate (birds and bats) and invertebrate (ants) predators on arthropod herbivores and plant damage in understory and canopy forest strata. The study finds that birds and bats (but not ants) have negative impacts on herbivore density, which, in turn, benefits plants by reducing leaf damage. Additionally, the effects of vertebrate predators are similar across strata. The authors also show that herbivore density and herbivory are greater in the understory compared to the canopy strata. Sivault etal. (2024) demonstrate that intraguild predation and niche overlap dictate the strength and direction of trophic cascades in forest ecosystems. In addition, these findings shed new light on forest ecology and conservation, especially considering the potential negative effects of climate change on top predators.

Effect of pollen consumption on development and intraguild predation of two predatory Coccinellidae

Many omnivorous predaceous coccinellids consume both pests like aphids and a range of plant-derived foods including pollen. It is critical to understand how plant-derived food like pollen could affect the fitness and interspecific interactions of predaceous coccinellids. This study investigated the effect of pollen consumption on the development, reproduction and intraguild predation (IGP) of two naturally co-existing aphidophagous ladybirds, Harmonia axyridis and Propylea japonica. Both species were provided with three diets including a moist canola pollen, the aphid Myzus persicae, or moist canola pollen together with aphids. The 1st instar larval of both H. axyridis and P. japonica could not survive and develop to the next larval stage when supplied with water alone. When fed on pollen only, 53 % of the H. axyridis larvae and 25 % of the P. japonica larvae successfully developed to adult. Both species exhibited an elongated development time, shorter larval body length and lower adult body weight than when offered with aphids and the mixed diet. In addition, P. japonica could not reproduce when fed on pollen alone. Interestingly, when pollen was provided as additional food, the overall IGP between larvae of H. axyridis and P. japonica was significantly reduced compared with water control or aphid as food alone. The results of this study indicated that pollen not only supports the survival of H. axyridis and P. japonica when prey is scarce, but also could benefit the co-existence of these species. For future study, it is necessary to investigate how pollinivory could benefit the fitness and biological control potential of H. axyridis and P. japonica under field conditions.

Predator becomes prey: Martial eagle predation of lion cubs in the greater Mara region, Kenya.

In many intact African savannah ecosystems, martial eagles are the top avian predator, while lions are the top terrestrial predator. Here, we report seven records of martial eagle predation or attempted predation of lion cubs in the greater Mara region, Kenya. These events resulted in the death of nine lion cubs, most of which were at least partially consumed, and are the first detailed records of this behaviour to be published. While these observations represent intraguild interactions, we suggest that they reflect neither intraguild predation nor interspecific killing. Rather, the ecology of both species coupled with the details of our records suggest that martial eagles opportunistically kill lion cubs purely to eat them. We hope that by publishing these records we will encourage others to share their observations of raptors predating on large mammalian carnivores, thus improving our understanding of a behaviour that we suspect may be more widespread than the current lack of evidence suggests.

A chemotaxis model of prey and predator of three species: Existence of unique global solutions

An intraguild predation model consisting of three species with densities s, u1, u2 in R2 is studied. Under certain natural conditions, namely the positivity of the initial values s0,u10 and u20, the solutions exist globally in time in the spaces of Lp∩H1, 1⩽p⩽∞. Our result, avoids the usual modifications on the chemotaxis term ∇⋅[u1∇u2].

Gelatinous filter feeders increase ecosystem efficiency

Gelatinous filter feeders (e.g., salps, doliolids, and pyrosomes) have high filtration rates and can feed at predator:prey size ratios exceeding 10,000:1, yet are seldom included in ecosystem or climate models. We investigated foodweb and trophic dynamics in the presence and absence of salp blooms using traditional productivity and grazing measurements combined with compound-specific isotopic analysis of amino acids estimation of trophic position during Lagrangian framework experiments in the Southern Ocean. Trophic positions of salps ranging 10–132 mm in size were 2.2 ± 0.3 (mean ± std) compared to 2.6 ± 0.4 for smaller (mostly crustacean) mesozooplankton. The mostly herbivorous salp trophic position was maintained despite biomass dominance of ~10-µm-sized primary producers. We show that potential energy flux to >10-cm organisms increases by approximately an order of magnitude when salps are abundant, even without substantial alteration to primary production. Comparison to a wider dataset from other marine regions shows that alterations to herbivore communities are a better predictor of ecosystem transfer efficiency than primary-producer dynamics. These results suggest that diverse consumer communities and intraguild predation complicate climate change predictions (e.g., trophic amplification) based on linear food chains. These compensatory foodweb dynamics should be included in models that forecast marine ecosystem responses to warming and reduced nutrient supply.

Identifying key drivers of extinction for Chitala populations: data-driven insights from an intraguild predation model using a Bayesian framework

Identifying key drivers of extinction for Chitala populations: data-driven insights from an intraguild predation model using a Bayesian framework

Resource supply and intraspecific variation in inducible defense determine predator–prey interactions in an intraguild predation food web

This study investigated the dynamics of reciprocal phenotypic plasticity entailing inducible defense and offense in freshwater ciliate communities in response to altered resource supply and the extent of intraspecific trait variation. Communities consisted of Euplotes octocarinatus (intraguild prey) capable of inducible defense to escape predation, Stylonychia mytilus (intraguild predator) capable of inducible offense to expand its prey spectrum, and Cryptomonas sp. (algal resource). The extent of inducible defense was tested in ten different Euplotes strains in response to freeze-killed Stylonychia concentrate, revealing significant differences in their width and length development. In a subsequent 30-day experiment, four strains were incubated in monoculture and mixture with Stylonychia under continuous and pulsed microalgae supply. The polyclonal Euplotes population outperformed the monoclonal populations, except one, which developed the most pronounced inducible defense and retained the highest biovolume. Stylonychia fluctuated in size, but dominated all communities irrespective of clonal composition. Pulsed resource supply promoted biovolume production of both species. However, periods of resource depletion resulted in more Stylonychia resting cysts, allowing Euplotes to resume growth. Our study provides new insights into interactions of induced defense and intraguild predation under variable environmental conditions, emphasizing the relevance of intraspecific trait variation for predator–prey interactions and community dynamics.

Intraguild species presence alters Aphidoletes aphidimyza (Diptera: Cecidomyiidae) and Aphidius gifuensis (Hymenoptera: Braconidae) foraging responses.

The predatory gall midge, Aphidoletes aphidimyza (Rondani), and tobacco aphid cocoon wasp, Aphidius gifuensis Ashmead, are important natural enemies of Myzus persicae (Sulzer) (Hemiptera: Aphididae). Predation by A. aphidimyza and A. gifuensis can regulate M. persicae; however, how interspecific interference competition affects their foraging efficiency is unknown. Here, we investigated the consumption and parasitization abilities of A. aphidimyza 3rd instar larva and A. gifuensis adults under various conditions. Consumption of parasitized aphids by A. aphidimyza 3rd instar larvae was significantly lower than that of nonparasitized controls, with a substantial increase in handling time. The presence of A. gifuensis adults did not significantly affect the predation capacity of A. aphidimyza larvae. Relative to controls, A. aphidimyza larvae predation trace (PT) and imago activity significantly decreased A. gifuensis parasitism rates at different aphid densities. Further, A. aphidimyza larvae PT increased the A. gifuensis handling time of M. persicae, whereas the presence of A. aphidimyza adults had the opposite effect. Coexistence with heterospecific natural enemies reduced the parasitic capacity of A. gifuensis, whereas A. aphidimyza larvae predation capability was influenced to a lesser extent. Our results demonstrate that intraguild interactions strongly influence the predatory and parasitic efficacy of A. aphidimyza and A. gifuensis, although the effect on A. gifuensis was more pronounced. For effective biological control of M. persicae using A. aphidimyza and A. gifuensis, we recommend releasing A. aphidimyza first to mitigate intraguild predation and enhance the overall success of the pest control program.

DYNAMICS OF A TRI-TROPHIC LEVEL MODEL WITH EXCESS FOOD NUTRIENT CONTENT AND INTRAGUILD PREDATION STRUCTURE

The dynamics of consumers can be affected by both nutrient-deficient food (low phosphorus (P) to carbon (C) ratio) and nutrient-excessive (high P:C) food, which is known as the stoichiometric knife-edge phenomenon. In this study, aiming to illustrate the responses of herbivores and omnivores to food with excessive P content, we present and analyze a tri-trophic level stoichiometric knife-edge model incorporating the intraguild predation structure. The model dynamics are theoretically examined, including the boundedness and positivity of solutions, the existence and stability of boundary equilibria, and the existence of positive equilibria. Numerical simulations show that the model has complex dynamics, encompassing chaotic-like oscillations, multiple types of bifurcations, long transients, and regime shifts. Moderate P levels facilitate the coexistence of the three species, whereas both lower and higher P levels result in the extinction of herbivores and omnivores. Specifically, the energy enrichment paradox occurs at low P levels. In contrast, the nutrient enrichment paradox occurs at high P levels, both of which are detrimental to the survival of herbivores and omnivores. Furthermore, the high-intensity predation of producers by omnivores helps to restrain the occurrence of chaotic dynamics. These findings contribute to a deeper understanding of the mechanisms of multi-species coexistence.

Nonlinear dynamics and pattern formation in a space–time discrete diffusive intraguild predation model

In this paper, the spatiotemporal dynamics and pattern formation of a space–time discrete intraguild predation model with self-diffusion are investigated. The model is obtained by applying a coupled map lattice (CML) method. First, using linear stability analysis, the existence and stability conditions for fixed points are determined. Second, using the center manifold theorem and the bifurcation theory, the occurrence of flip, Neimark-Sacker, and Turing bifurcations are discussed. It is shown that the patterns obtained are results of Turing, flip, and Neimark-Sacker instabilities. Numerical simulations are performed to verify the theoretical analysis and to reveal complex and rich dynamics of the model, such as times series, maximal Lyapunov exponent, bifurcation diagrams, and phase portraits. Interesting patterns like spiral pattern, polygonal pattern, and the combinations of patterns of spiral waves and stripes are formed. The CML model’s results help to understand how a spatially extended, discrete intraguild predation model forms complex patterns. Notably, the continuous reaction–diffusion counterpart of the model under study is incapable of experiencing Turing instability.

Topological traits are associated with the prevalence of IGP modules in empirical food webs

Exploring how food webs are assembled from basic modules is charming and crucial for understanding how communities are self-organized. As one of the basic modules, intraguild predation (IGP) consists of a prey being consumed by both an intermediate and a top predator, with the former also being consumed by the latter (thus encompassing both predation and competition). This interaction has been shown to govern food web stability, and therefore underpin the organization of network structures. While some studies have been made in understanding the factors and mechanisms behind the prevalence of IGP modules in food webs, the specific role of food web topological structures in relation to these modules remains largely unexplored and is not well understood. Here, 103 food webs were analyzed, and we found that the number of modules in each food web was largely determined by taxon richness and connectance. After controlling richness and connectance, the specific scale-free pattern and core-periphery structure of empirical food webs explains the higher prevalence of IGP modules in empirical food webs better than by chance. Lastly, the loss of taxa which supported large number of IGP modules would lead to serious damage to food web robustness, indicating the keystone role of these taxa in maintaining food web structure and stability. Our results provide new insight into the assembly of empirical food webs from the perspective of IGP modules.

When the predator becomes the prey: new records of intraguild predation among Central American and Caribbean arachnids (Arachnida: Amblypygi, Araneae, Scorpiones)

ABSTRACT Intraguild predation occurs when an organism preys on a competitor. This ecological interaction can have considerable consequences on the population dynamics of predators and indirectly affect their prey. In arachnids, it is a quite common phenomenon, but it has been poorly documented in the Neotropical region. Here, we present records of 16 species feeding on other 14 species of arachnids. The most common families that acted as predators were Buthidae (Scorpiones) and Salticidae (Araneae), while the most common prey were members of the families Araneidae and Ctenidae (Araneae). In our survey, Drake Bay, in Costa Rica, is overrepresented due to years of systematic observations by two of the coauthors.

Ecological restoration enhanced the stability of epiphytic microbial food webs of submerged macrophytes: Insights from predation characteristics of epiphytic predators

The application of various submerged macrophytes for ecological restoration has gained increasing attention in urban lake ecosystems. The multitrophic microbial communities that colonized in various submerged macrophytes constitute microbial food webs through trophic cascade effects, which affect the biogeochemical cycles of the lake ecosystem and directly determine the effects of ecological restoration. Therefore, it is essential to reveal the diversity, composition, assembly processes, and stability of the microbial communities within epiphytic food webs of diverse submerged macrophytes under eutrophication and ecological restoration scenarios. In this study, we explored the epiphytic microbial food webs of Vallisneria natans and Hydrilla verticillata in both eutrophic and ecological restoration regions. The obtained results indicated that the two regions with different nutrient levels remarkably affected the diversity and composition of epiphytic multitrophic microbial communities of submerged macrophytes, among them, the community composition of epiphytic predators were more prone to change. Secondly, environmental filtering effects played a more important role in driving the community assembly of epiphytic predators than that of prey. Furthermore, the generality and intraguild predation of epiphytic predators were significantly improved within ecological restoration regions, which increased the stability of epiphytic microbial food webs. Additionally, compared with Hydrilla verticillata, the epiphytic microbial food webs of Vallisneria natans exhibited higher multitrophic diversity and higher network stability regardless of regions. Overall, this study focused on the role of the epiphytic microbial food webs of submerged macrophytes in ecological restoration and uncovered the potential of epiphytic predators to enhance the stability of microbial food webs, which may provide new insights into the development of ecological restoration strategies.

Beyond predator richness: How diversified cropping can enhance pest regulation

AbstractResearch Highlight discussing: Heinen, J.; Dominguez, V.; Aguilera, G.; Malsher, G.; Vesterinen, E.; Roslin, T.; Bommarco, R.; Bartomeus, I. (2024). Diversified cropping strengthens herbivore regulation by providing seasonal resource continuity to predators. Journal of Applied Ecology, https://doi.org/10.1111/1365‐2664.14674. Crop monocultures consist of homogenous agroecosystems highly dependent on pesticides for pest regulation and mineral fertilisation for maintaining plant nutrition, representing the least resilient system. Agricultural diversification practices can increase heterogeneity in agroecosystems, resulting in greater richness of arthropod predators and enhanced ecological services. Among natural enemies of pests, generalist predators are important for pest regulation as they prey on diverse arthropod pests and be present throughout the season. However, since they consume other predators (intraguild predation) and soil fauna, it is uncertain whether enhanced richness of generalist predators translates into improved pest regulation. The study by Heinen et al. examined how diversified crop rotation and organic fertilisation influenced predator–prey interactions throughout the cropping cycle in cereal fields. The predators' diet preference shifted over the growing season, indicating that soil fauna is an important resource for recruitment and maintenance of predators early in the season. Although intraguild predation was considerably high, it decreased across the season in fields with the greatest level of diversification, where predation of pests remained stable. This study demonstrated how diversified cropping is important for providing resource continuity with alternative prey (soil fauna and predators) over crop‐growing season, enhancing predator richness and herbivore regulation.

Importance of Host Feeding in the Biological Control of Insect Pests: Case Study of Egg Parasitoid Species (Hymenoptera: Chalcidoidea: Trichogrammatidae).

Over recent decades, intraguild predation (IGP) has attracted special attention, both from the theoretical and practical standpoints. The present paper addresses the interference competition between two Trichogramma species (egg parasitoids)-on the one hand, the extrinsic interactions (i.e., the indirect competition between female T. achaeae and T. brassicae), and on the other, the intrinsic interactions between the larvae of both species. Furthermore, T. achaeae is a better competitor than T. brassicae due to a dual mechanism-the former acts as a facultative hyperparasitoid of the latter, exclusively considering parasitism relationships as well as presenting predation activity by host feeding, which gives preference to eggs previously parasitized by T. brassicae over non-parasitized eggs. Both mechanisms are dependent on the prey density, which is demonstrated by a change in the functional response (i.e., the relationship between the numbers of prey attacked at different prey densities) of T. achaeae adult female-it changes from type II (i.e., initial phase in which the number of attacked targets increases hyperbolically and then reaches an asymptote, reflecting the handling capacity of the predator), in the absence of competition (an instantaneous search rate of a' = 9.996 ± 4.973 days-1 and a handling time of Th = 0.018 ± 0.001 days), to type I (i.e., linear increase in parasitism rate as host densities rise, until reaching a maximum parasitism rate, and an instantaneous search rate of a' = 0.879 ± 0.072 days-1 and a handling time of Th ≈ 0) when interference competition is present. These results show that there is a greater mortality potential of this species, T. achaeae, in conditions of competition with other species, T. brassicae in this case. Based on this, their implications in relation to the biological control of pests by parasitoid species are discussed.