Biology subjects

Frago, E.

Publications and source records attributed to Frago, E..

3 recordsLinked to original sources

bioRxiv2026

Predator coexistence and herbivore suppression are shaped by predator functional types in intraguild predation modules

Coexistence of multiple predators in ecological communities and their combined effects on the abundance and diversity of shared prey are often difficult to predict. In some theoretical models, predator coexistence is limited by antagonistic interactions, especially in the form of intraguild predation (IGP) that typically leads to out-competition between predators and high prey densities. However, empirical studies show that predator coexistence is common even in the presence of IGP. This discrepancy between theoretical expectations and empirical observations can be highly relevant for practical applications like using multiple natural enemies for pest suppression in agriculture. It is proposed that greater functional differences between natural enemies (i.e. predators) could reduce competition and overcome the negative effects of IGP, thereby promoting their coexistence and enhancing herbivore (i.e. prey) suppression. In this study, we theoretically explore this proposition. We develop a theoretical model based on the types of natural enemies of aphids to identify how functional differences between predators in IGP modules affect predator coexistence and herbivore suppression. We show that pairwise combinations of four functional predator types (ladybird, predatory bug, hoverfly, and parasitoid) can increase the coexistence range for different intraguild predation and competition strengths between predators (IGP symmetry), along a productivity gradient. This outcome depends on the external food input rate for the predatory bug and hoverfly types, and on their position as IG predator or IG prey. Herbivore suppression was primarily driven by IGP symmetry (i.e. the relative intraguild predation and exploitative competition strength between predators) and was especially pronounced in competitive-like modules where the IG predator was excluded for most scenarios. However, for some competitive-like IGP modules with predatory bug and hoverfly types, both predators can persist and provide a high herbivore suppression across increasing productivity. Our results can help explain experimental findings in conservation biocontrol, where coexistence between natural enemies is joined with effective herbivore suppression, and offer additional support for the role of functional diversity in reconciling theoretical predictions with experimental observations in multiple-predator communities.

ecology↗

bioRxiv2020

Joint species distributions reveal the combined effects of host plants, abiotic factors and species competition as drivers of community structure in fruit flies

AO_SCPLOWBSTRACTC_SCPLOWThe relative importance of ecological factors and species interactions for phytophagous insect species distributions has long been a controversial issue. Using field abundances of eight sympatric Tephritid fruit flies on 21 host plants, we inferred flies realized niches using joint species distribution modelling and network inference, on the community as a whole and separately on three groups of host plants. These inferences were then confronted to flies fundamental niches estimated through laboratory-measured fitnesses on host plants. Species abundances were mainly determined by host plants followed by climatic factors, with a minor role for competition between species sharing host plants. The relative importance of these factors mildly changed when we focused on particular host plant groups. Despite overlapping fundamental niches, specialists and generalists had almost distinct realized niches, with possible competitive exclusion of generalists by specialists on Cucurbitaceae, and different assembly rules: specialists were mainly influenced by their adaptation to host plants while generalist abundances varied regardless of their fundamental host use.

ecology↗

bioRxiv2019

A meta-analysis on the benefits and costs of hosting secondary endosymbionts in sap-sucking insects

Herbivorous insects host various bacteria that help them to feed, grow, and survive. Sap-sucking insects, in particular, feed on a nutrient-poor resource and have evolved obligate symbioses with nutritional bacteria for survival. Additionally, sap-sucking insects have formed facultative associations with bacterial symbionts that are not essential for growth and survival but assumed to confer some benefits, such as resistance to natural enemies. Several recent reviews have highlighted the importance of these symbionts in understanding their hosts biology, but currently there is a lack of a quantitative and systematic analysis of the published evidences exploring whether the different endosymbionts are actually beneficial or not. In this meta-analysis we explored the potential costs and benefits associated with hosting facultative endosymbionts in sap-sucking insects. Our first result is that most of the empirical experimental data information is limited to a few species of aphid and one species of whiteflies. Through the meta-analysis we showed that hosting symbionts generally leads to costs through increased development time, reduced longevity, and reduced fecundity, and benefits via increased resistance to parasitic wasps in sap-sucking insects. However, the impact of these costs and benefits was strongly insect and symbiont species dependent. Many of the insects studied are agricultural pests, and understanding the impact of bacterial symbionts on their hosts across different environments can benefit sustainable management of greenhouses and agricultural land.

ecology↗