Habitat segregation of sympatricMnaisdamselflies (Odonata: Calopterygidae): microhabitat insolation preferences and competition for territorial space

Abstract

Distribution and abundance of sympatric Mnais costalis and M. pruinosa damselflies were studied in a low mountain stream in Shiga, Japan, from 2008 through 2012. The reproductive seasons of the two species overlapped almost entirely: both species emerged in early May and disappeared in late June each year. Males of both species hold territories within the same stretch of the river; however, M. costalis was more abundant on the lower stream, while M. pruinosa was more abundant on the upper stream. Canopy openness varied at territorial sites. Results of these observations suggest that habitat segregation of the two species is due to different preference for light/shade conditions. Morisita's R δ index suggests that interspecific exclusion (or avoidance) contributes to the habitat segregation of the two species.

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

“…We have previously shown that in the field M. costalis males have higher body temperatures, reflecting their microhabitat preference for sunny sites, while M. pruinosa males have lower body temperatures, reflecting their preference for shady environments (Okuyama et al, 2013). In our previous paper (Okuyama et al, 2013), we demonstrated microhabitat segregation in sympatric Mnais damselflies (Odonata: Calopterygidae). Males of both species hold territories within the same stretch of the river in most of Kinki region in central Japan.…”

“…Males of both species hold territories within the same stretch of the river in most of Kinki region in central Japan. However, M. costalis were more abundant on the lower stream, while M. pruinosa were more abundant on the upper stream (Nomakuchi, 1992;Okuyama et al, 2013;Suzuki & Tamaishi, 1982). Measurement of canopy openness using hemispherical photographs with a fisheye converter revealed that M. costalis preferred sunny microhabitats while M. pruinosa preferred shady microhabitats (Okuyama et al, 2013).…”

“…However, M. costalis were more abundant on the lower stream, while M. pruinosa were more abundant on the upper stream (Nomakuchi, 1992;Okuyama et al, 2013;Suzuki & Tamaishi, 1982). Measurement of canopy openness using hemispherical photographs with a fisheye converter revealed that M. costalis preferred sunny microhabitats while M. pruinosa preferred shady microhabitats (Okuyama et al, 2013). Analyses of the overlap in distributions using Morisita's R δ index (Morisita, 1959) showed that there was no significant effect of male density of either species (Okuyama et al, 2013).…”

“…This is probably because environmentally dependent body temperature influences physiological and behavioral activities (Heinrich, 1981(Heinrich, , 1993, and individual fitness (Huey, 1991;Huey & Berrigan, 2001;Tsubaki, Samejima, & Siva-Jothy, 2010;Willmer, 1991). We have previously shown that in the field M. costalis males have higher body temperatures, reflecting their microhabitat preference for sunny sites, while M. pruinosa males have lower body temperatures, reflecting their preference for shady environments (Okuyama et al, 2013). In our previous paper (Okuyama et al, 2013), we demonstrated microhabitat segregation in sympatric Mnais damselflies (Odonata: Calopterygidae).…”

“…Microhabitat partitioning in space or time is a widespread mechanism of coexistence (Cody & Brown, 1969;Konuma & Chiba, 2007;Kuno, 1992;McLain & Pratt, 1999;McLain & Shure, 1987;Okuyama, Samejima, & Tsubaki, 2013;Singer, 1990). However, it is usually difficult to show whether resource competition or interspecific sexual interaction is the direct cause of microhabitat partitioning.…”