Ecological correlates of polyphenism and gregarious roosting in the grass yellow butterfly Eurema elathea (Pieridae)

Abstract

Eurema elathea adults were census weekly (1992-1994) in six night-roosts around a forest fragment on a farm, and in two roosts in the urban area of Uberlândia, Minas Gerais, Brazil. Males were grouped in six phenotypic classes. These were based on a range between having a conspicuous wide black bar at the dorsal forewing inner margin (wet season dark morphs) and the absence of that bar (dry season light morphs). The body mass and wing area of co-occurring morphs were compared: differents morphs showed similar means. The abundance of butterflies and morph frequencies varied in close relation to humidity (rainfall). Individuals were infrequent and monomorphically dark in the wet season while light morphs predominated in dry periods when population peaked. A lower fraction of recaptured individuals and higher recruitment were recorded compared to other night-roosting butterflies. Dispersal potential was similar between the sexes and varied seasonally with a more sedentary population in dry periods. The maximum residence time recorded was 91 days for a female and 84 days for a male. The fraction of individuals that moved from one roosting site to another was similar in both sexes and male morphs, but significantly higher on the farm than in the urban area. Also, a significantly higher fraction (21.3%) of marked butterflies was recaptured in the urban area than on the farm (15.6%), suggesting a behavioral modification for sedentariness in the urban individuals. The selective forces shaping a gregarious roosting habit in E. elathea and other butterflies are discussed and a protocooperational strategy for saving energy is proposed.

Population biology of three satyrine species (Nymphalidae: Satyrinae) in a suburban habitat

“…Ruszczyk 1986Ruszczyk , 1987; Ruszczyk and Araújo 1992; Ruszczyk and Nascimento 1999 and references therein), studies of urban ecology in tropical butter ies have increased considerably, with a strong focus in community ecology (Brown and Freitas 2002;Collier et al 2006;Iserhard et al 2019 and references therein). In this respect, studies focusing on population biology of urban tropical butter ies are scarce and restricted to very few groups (Ruszczyk and Nascimento 1999;Vanini et al 1999;Ruszczyk et al 2004; Tourinho and Freitas 2009).…”

Comportamento de agregação noturna dos machos de Actinote surima surima (Schaus) (Lepidoptera, Heliconiinae, Acraeini)

“…MALLET (1986) relata a formação dos "gregarious roosting" (poleiros gregários) em muitas espécies de Heliconius Kluk, 1780: H. erato (Linnaeus, 1758), H. charitonia (Linnaeus, 1767), H. sapho hewitsoni Hewitson, 1875, H. melpome (Linnaeus, 1758, H. cydmo pachinus Salvin, 1871, H. ismenius Latreille, [1817 e H. hecale (Fabricius, 1776); grupo irmão de Acraeini segundo PENZ & PEGGIE (2003). RUSZCZYK et al (2004), usando como exemplo Eurema elathea (Cramer, 1777) (Pieridae, Coliadinae)) discutem o significado ecológico e evolutivo do polifenismo e das agregações noturnas.…”