Smaller damselflies have better flight performance at lower body temperature: implications for microhabitat segregation of sympatricMnaisdamselflies

Abstract

In many cases where two closely related species coexist, ecological interaction or reproductive interference drive species to diversify in their body size and/or other signal traits, often concurrently with microhabitat segregation. However, it is usually unclear how character diversification is associated with microhabitat segregation. We performed laboratory experiments using males of two damselfly species (Mnais costalis and Mnais pruinosa) collected from a syntopic site in Shiga Prefecture, Japan. We analyzed the effects of body temperature and body size on three indices of flight performance: wing-beat frequency and flight speed as measures of thrust production, and minimum body temperature for flight (MBTF). The results showed that the MBTF was correlated with body size: the smaller species (M. pruinosa) flew better than the larger species (M. costalis) in a cool environment. The initial flight speed was positively correlated with body temperature, but negatively correlated with body size. The wing-beat frequency was also positively correlated with body temperature, but negatively correlated with body size. The combined effects of body size and body temperature on wing-beat frequency meant that overall, there was no significant difference in initial flight speed. We suggest that the effect that body size and temperature have on flight performance explains the previously documented microhabitat segregation occurring between these two species, with the larger M. costalis preferring sunny environments and M. pruinosa preferring shady environments.

Range shifting species reduce phylogenetic diversity in high latitude communities via competition

“…Damselfly performance is highly limited by climate, with higher temperatures shown to increase growth rates (Corbet & May ; Nilsson‐Ortman et al . ) and adult flight performance (Okuyama, Samejima & Tsubaki ). Higher temperatures are also correlated with increased damselfly population densities in high‐latitude habitats (Lancaster et al .…”

“…Damselflies (Odonata: Zygoptera) are semi-aquatic, predatory insects, which exhibit strong intra-and interspecific competition at both larval (aquatic) and adult (terrestrial) life stages (Convey 1988;Worthen & Patrick 2004). Damselfly performance is highly limited by climate, with higher temperatures shown to increase growth rates (Corbet & May 2008;Nilsson-Ortman et al 2013) and adult flight performance (Okuyama, Samejima & Tsubaki 2015). Higher temperatures are also correlated with increased damselfly population densities in high-latitude habitats (Lancaster et al 2015).…”

Field estimates of fitness costs of the pace‐of‐life in an endangered damselfly

“…In males, larger body size has also been shown to confer mating advantages, particularly in territorial species because larger males are better at acquiring and defending territories (Alcock, 1981;Baker, 1983;Choe & Crespi, 1997). However, there is also evidence of selection for smaller or intermediate body size (Cordero, Carbone, & Utzeri, 1997;Okuyama, Samejima, & Tsubaki, 2015;Rivas-Torres, Sanmartín-Villar, Gabela-Flores, & Cordero-Rivera, 2017;Rivera, 2000;Zamudio, Huey, & Crill, 1995). For instance, larger body might be associated with disadvantages such as longer development time, higher nutritional requirements and lower flight performance (Blanckenhorn, Preziosi, & Fairbairn, 1995;Clutton-Brock, Albon, & Guinness, 1985).…”