Can multitrophic interactions shape morphometry, allometry, and fluctuating asymmetry of seed-feeding insects?

Abstract

Body size is commonly associated with biological features such as reproductive capacity, competition, and resource acquisition. Many studies have tried to understand how these isolated factors can affect the body pattern of individuals. However, little is known about how interactions among species in multitrophic communities determine the body shape of individuals exploiting the same resource. Here, we evaluate the effect of fruit infestation, parasitism rate, and seed biomass on size, allometric and asymmetric patterns of morphological structures of insects that exploit the same resource. To test it, we measured 750 individuals associated with the plant Senegalia tenuifolia (Fabaceae), previously collected over three consecutive years. Negative allometry was maintained for all species, suggesting that with increasing body size the body structure did not grow proportionally. Despite this, some variations in allometric slopes suggest that interactions in a multitrophic food web can shape the development of these species. Also, we observed a higher confidence interval at higher categories of infestation and parasitism rate, suggesting a great variability in the allometric scaling. We did not observe fluctuating asymmetry for any category or species, but we found some changes in morphological structures, depending on the variables tested. These findings show that both allometry and morphological trait measurements are the most indicated in studies focused on interactions and morphometry. Finally, we show that, except for the fluctuating asymmetry, each species and morphological structure respond differently to interactions, even if the individuals play the same functional role within the food web.

The relationship between host plant traits and biodiversity across three sympatric seed‐feeding tri‐trophic systems in a tropical region of Brazil

“…As a result, seeds with higher Allorhogas spp. abundance are expected to be smaller, as reported before (de Oliveira, Monteiro, & Faria, 2020; de Oliveira, Monteiro, Morales‐Silva, et al, 2020; Tuller et al, 2015).…”

“…The impact of plant traits on the host–parasitoid systems has long been recognised (Bukovinszky et al, 2008; Ode, 2006). From a food web perspective, plant traits have a direct impact on both insect morphology and size (de Oliveira, Monteiro, & Faria, 2020; de Oliveira, Monteiro, Morales‐Silva, et al, 2020; de Sousa‐Lopes et al, 2020; Silva et al, 2017), behaviour and life history (Ode, 2006; Underwood & Rausher, 2000). According to Bukovinszky et al (2008), up to three trophic levels can be affected directly and indirectly by the quantity and quality of the resource.…”

“…First, certain characteristics of the host plant (e.g., number and size of seeds and fruits) have been identified as key factors in promoting bottom‐up effects in these systems, influencing insect–parasitoid interactions, structure and community complexity (Bukovinszky et al, 2008; Morales‐Silva et al, 2018). Furthermore, host plant quality and quantity directly influence herbivore performance (e.g., fecundity, body size) and reproduction (de Oliveira, Monteiro, & Faria, 2020; Janzen, 1971; Prince et al, 2011; Stillwell et al, 2007), as well as mediate indirect effects in food webs because these herbivores are consumed by other species in complex tri‐trophic interactions (Reimchen, 1997; Schmitz, 2008). Thus, tri‐trophic systems rooted with host plants in the Fabaceae can inform the richness, abundance, distribution and interaction of herbivores and parasitoids.…”

Limitations of allometry, morphometry, and fluctuating asymmetry in detecting environmental stress caused by lead soil contamination in aphids under field conditions

“…We verified the relationship between the size of the measured organs and the FA value (Palmer and Strobeck, 1986). Hence, we calculated FA according to the equation: FA = (R -L), (Palmer and Strobeck, 1986), where R is the size measured on the right side and L is the size measured on the left side, for both the antennae and the tibiae (Grześ et al, 2015;Souza et al, 2018;Oliveira et al, 2020). We applied linear mixed models (LMMs) using the function lmer from the lme4 package, considering the treatments as the explanatory variables and individual identity (measurement error) and plant identity as the random variables (Palmer, 1994).…”

“…1c). The appendages measurements occur three times on the right and left sides on different days to exclude measurement errors from the FA tests (Palmer and Strobeck, 1986;Graham et al, 2010;Souza et al, 2018;Oliveira et al, 2020).…”