Evaluating intraspecific variation in insect trait analysis

Abstract

1. Intraspecific variation plays important roles in ecology and evolution. Yet, information on how species and populations vary remains scarce, particularly for insects and regarding functional traits. This lack of knowledge can be problematic in trait-based ecology because traditional approaches assume negligible intraspecific variation, even for analyses that assess highly variable taxa.2. We measured 291 Arctic fritillary butterflies (Boloria chariclea) to assess the intraspecific variation in one population of this species, evaluating (i) how wingspan of Arctic fritillaries varies in relation to the other species of its community, and (ii) how well wingspan, a measure of body size, predicts weight, a measure of body mass.3. Wingspan of Arctic fritillaries varied between 2.62 and 4.07 cm, with the 95% interval range, including ∼33% (14/42) of the species in the community, and ∼30% (84/279) of the butterflies of Canada. The relationship between wingspan and weight was significant (β wingspan = 0.002, SE = 0.0008, P < 0.001), but relatively weak (R 2 adj = 0.31, F 2,288 = 67.82, P < 0.001).4. We discuss our findings in relation to the assumption of species homogeneity and the use of proxies in the analysis of species traits, complementing our case study with simulations to illustrate how intraspecific and interspecific variation interact in determining when traditional trait analyses are robust. We suggest entomologists interested in trait analyses should critically evaluate how intraspecific variation could affect their inference, especially when evaluating species that are highly sexually dimorphic, phenotypically plastic, and/or distributed across broad environmental and spatial clines.

Concepts and applications in functional diversity

“…However, as emphasized by a few comparative studies across a selection of methods and metrics (Junker et al, 2016;Mouchet et al, 2010;Wong & Carmona, 2020), this is rarely the case. Discrepancies are partly related to the intrinsic differences of each approach (Table 2), and partly to the scale of analysis and methodological choices on how to handle trait variability (Gentile, Bonelli, & Riva, 2020;Wong & Carmona, 2020). We believe it would be needed to comprehensively analyse properties of the existing methods using either real-world data or simulations based on different combinations of traits, scales of organization, and input parameters.…”

Concepts and applications in functional diversity

“…However, as emphasised by a few comparative studies across a selection of methods and metrics (Junker et al, 2016;Legras et al, 2020;Mammola & Cardoso, 2020;Mouchet et al, 2010;Wong & Carmona, 2021), this is rarely the case. Discrepancies are partly related to the intrinsic differences of each framework (Table 2), and partly to the scale of analysis and methodological choices on how to handle trait variability (Gentile et al, 2020;Wong & Carmona, 2021), as well as the number of traits considered (Legras et al, 2020).…”

A Vertical stratification of arthropods in the dry ecosystems of Colombian Guyana: morphological patterns and their ecological implications

“…The influence of climate on insects for example, triggers a series of morpho-physiological transformations that include strategies of evasion, adaptation, or resistance with great ecological and evolutionary implications (Colinet et al, 2015;Danks, 2007). Characteristics such as size and color patterns in insects can influence inter-and intraspecific competition, thermoregulation, activity levels, and resource use (Gentile et al, 2021;Peters, 1983), since ectothermic organisms depend on external sources of heat for the internal regulation of their body temperature (Chown & Nicolson, 2004;Forsman et al, 2008).…”