Behavioural modes in butterflies: their implications for movement and searching behaviour

Abstract

Animals move in 'modes' where movement patterns relate to specific behaviours. Despite much work on the movement of butterflies, their behavioural modes are relatively unexplored. Here we analysed the behaviour of the model butterfly species the meadow brown, Maniola jurtina. We identified modes in both sexes and across habitats varying in resource density. We found that, in nectar-rich habitats, males had more diverse behaviour than females, engaging in a unique 'high-flight' mode associated with mate search, whereas females were primarily nectaring or inactive. In nectar-poor habitats, both sexes were similar, switching between flight and inactivity. We also identified the movement parameters of the modes, finding that, for both sexes, movements associated with nectaring were slower and more tortuous and, for males, the mode associated with mate searching was straighter and faster. Using an individual-based random-walk model, we investigated the effects of behaviour on movement predictions by comparing a mode-switching model with a version including intraspecific variation and another assuming homogeneity between individuals. For both sexes, including modes affected the mean and shape of the displacement rate compared to models assuming homogeneity, although for females modes increased displacement 1.5 times while for males they decreased it by a third. Both models also differed substantially from models assuming intraspecific variation. Finally, using a new model of search behaviour we investigated the general conditions under which individuals should engage in an exclusive search for host plants or receptive females. Parameterized for M. jurtina, the model predicted males should engage exclusively in mate search, but females only when searching is very efficient. The model provides a framework for analysing the searching behaviour of other butterfly species.

Influence of habitat quality and resource density on breeding‐season female monarch butterfly Danaus plexippus movement and space use in north‐central USA agroecosystem landscapes

“…Previous studies indicate movements are influenced by habitat quality. Short steps and torturous flight patterns are typically observed in resource‐rich habitat patches, consistent with foraging behaviour, while directed movements are reported when traversing the matrix or low‐quality habitat (Delattre et al., 2010; Evans, Oliver, et al., 2020; Evans, Sibly, et al., 2020; Haddad, 1999; Kral‐O'Brien & Harmon, 2021; Schultz et al., 2012; Zalucki, 1983; Zalucki & Kitching, 1982). Consistent with these general associations, Zalucki and Kitching (1982) reported tortuous monarch movement in manipulated areas with high densities of resources.…”

“…For example, Fisher and Bradbury (2021a) observed 90% of 145 monarchs released in a sod field oriented downwind and away from plant resources, likely in response to the resource‐devoid and exposed landcover. Most butterfly movement studies do not report wind direction (Evans, Oliver, et al., 2020; Evans et al., 2019; Fernández et al., 2016; Schultz et al., 2012) or assume that wind direction and wind speed would not confound experimental designs (Evans, Sibly, et al., 2020; MacDonald et al., 2019; Merckx & Van Dyck, 2007). Our studies indicate that the collection of wind direction data can help interpret the orientation of movement.…”

Flight behaviour diverges more between seasonal forms than between species inPierisbutterflies

“…Although the benefits of adopting a curvy flight pattern for foraging in a dispersed resource environment remains hypothetical, the higher flight curvature of spring Pieris may have evolved jointly with a specialised foraging strategy. Next, males and females may exhibit distinct flight patterns across the landscape due to differences in their resource utilization strategies and habitat use (Evans et al 2020). In that sense, the divergent flight behaviour of spring Pieris might be adaptive and linked to movements across the landscape, which might result in more effective exploitation of newly emerging feeding and oviposition resources (Cant et al, 2005).…”

“…However, our understanding of which specific wing traits influence distinct flight behaviours, including agility and manoeuvrability, remains unclear. Seasonal flight behaviours may be adaptive as, for example, increased manoeuvrability seems to be advantageous when foraging for newly emerging feeding resources (Evans et al, 2020). Furthermore, increasing wing area might enhance dispersal ability, as quantified in migrating generations vs. sedentary populations of Danaus butterflies (Tenger-Trolander et al, 2023).…”

“…For example, it has been hypothesised that the spring individuals of both Pieris species are better adapted to explore the scattered feeding and oviposition resources on their natal patch, while the summer forms might be better adapted for dispersal to novel localities (Fric et al, 2006; Shkurikhin & Oslina, 2016). Indeed, movements associated with nectaring were slower and more tortuous than movement associated with mate searching in a satyrid butterfly (Evans et al, 2020). Furthermore, increasing wing area might enhance dispersal ability, as quantified in migrating generations vs. sedentary populations of Danaus butterflies (Tenger-Trolander et al, 2023).…”