Seasonal plasticity in anti-predatory strategies: matching of color and color preference for effective crypsis

Abstract

word count: 266 words Total word count:ABSTRACT Effective anti-predatory strategies typically require matching appearance and behavior in prey, and there are many compelling examples of behavioral repertoires that enhance the effectiveness of morphological defenses. When protective adult morphology is induced by developmental environmental conditions predictive of future predation risk, adult behavior should be adjusted accordingly to maximize predator avoidance. While behavior is typically strongly affected by the adult environment, developmental plasticity in adult behavior -mediated by the same pre-adult environmental cues that affect morphology -could ensure an effective match between anti-predatory morphology and behavior. The coordination of environmentally-induced responses may be especially important in populations exposed to predictable environmental fluctuations (e.g. seasonality). Here, we studied early and late life environmental effects on a suite of traits expected to work together for effective crypsis. We focused on wing color and background color preference in Bicyclus anynana, a model of developmental plasticity that relies on crypsis as a seasonal strategy for predator avoidance. Using a full-factorial design, we disentangled effects of developmental and adult ambient temperature on both appearance and behavior. We showed that developmental conditions affect both adult color and color preference, with temperatures that simulate natural dry season conditions leading to browner butterflies with a perching preference for brown backgrounds. This effect was stronger in females, especially when butterflies were tested at lower ambient temperatures. In contrast to the expectation that motionlessness enhances crypsis, we found no support for our hypothesis that the browner dry-season butterflies would be less active. We argue that the integration of developmental plasticity for morphological and behavioral traits might improve the effectiveness of seasonal anti-predatory strategies.

Developmental plasticity for male secondary sexual traits in a group of polyphenic tropical butterflies

“…Several males from each family were sacrificed and the three MSP components were extracted by soaking one fore-and one hind-wing of each individual in 500 μl of hexane. The amount of each component of the MSP, namely MSP1, MSP2 and MSP3, was quantified using gas-chromatography (details in van Bergen et al 2013) and the remaining wings from each sample were stored in entomological envelopes at -20°C. Here we quantified the size of the androconial patches of these samples (n = 67) using the procedure described below.…”

“…Temperature experienced during the late larval stage is an important environmental inducer of the seasonal forms both in the field and in the laboratory; lower or higher temperatures act as a cue for forthcoming dry or wet seasons, respectively (Kooi andBrakefield 1999, Brakefield et al 2007). Moreover, developmental plasticity in mycalesine butterflies involves coordinated responses of morphological, physiological, behavioural and life history traits which together provide an adaptive response to climate instability (Oostra et al 2014, Mateus et al 2014, Nokelainen et al 2018, van Bergen and Beldade 2018.…”

To mate, or not to mate: The evolution of reproductive diapause facilitates insect radiation into African savannahs in the Late Miocene

“…In contrast, the dry season form generally lack these eyespots, and they rely mainly on crypsis when at rest on dead leaf litter for survival against predators hunting by sight (Lyytinen et al, , ; Prudic et al, ). Along with the wing pattern changes, both forms differ in a suite of other morphological, behavioural, physiological and life‐history traits, as an integrated response which is linked by a common hormonal switch as has been extensively explored in laboratory settings in a single species Bicyclus anynana (Oostra et al, , ; van Bergen & Beldade, ; van Bergen et al, ). Such an integrated system helps to maintain a season‐specific adaptive phenotype by making use of environmental cues to predict approaching seasonal shifts (Brakefield & Reitsma, ; Kooi & Brakefield, ).…”

Complex multi-trait responses to multivariate environmental cues in a seasonal butterfly

“…This species exhibits two alternative seasonal forms (dry and wet) which correspond to a cool and a warm season, respectively. In addition to differences in morphology (Brakefield and Reitsma 1991), physiology (Oostra et al 2011), and behaviour (van Bergen and Beldade 2019), the forms also differ markedly in their life-history traits (e.g. Oostra et al 2011).…”