Brief Mating Behavior at Dawn and Dusk and Long Nocturnal Matings in the Butterfly Melanitis leda

Abstract

Information on the mating system of an insect species is necessary to gain insight into sexual selection and population structure. Male territoriality of the common evening brown butterfly Melanitis leda has been studied in the wild, but other aspects of its mating system remain largely unknown. For a population of M. leda in South India, we observed male-male and male-female interactions in captivity, measured mating duration and spermatophore mass, and also determined the degree of polyandry in the wild. We found that mating behavior takes place for short periods of time around dawn and dusk. Our observations corroborate that males compete in aerial combats (twirling) and interfere with mating pairs. In the morning, they may use shivering to warm up. Females can twirl with males and refuse mating by pointing their abdomens upwards or by flying away. Males court females by fluttering their wings while perched behind females, and then initiate copulation by curling their abdomens ca. 180 degrees sideways to make genital contact. While in the morning, matings lasted on average one hour and twenty-three minutes and never exceeded three hours, in the evening, matings could be of similar duration, but 42% of butterflies only separated when dawn was approaching. However, such long nocturnal matings did not result in heavier spermatophores. The first spermatophore of a male tended to be larger than subsequent spermatophores. Together with previous studies on this species, our findings suggest that males compete mainly through territorial defense (as reported before), courtship performance, and interference, and to a lesser extent by providing spermatophores, while females exert some control over the mating system by the timing of their receptivity and mate choice.

Seasonal dynamics and polyphenism of butterfly communities in the coastal plains of central Western Ghats, India

“…Another seasonal trait -polyphenism, with its ecological cause and effect -is strongly influenced by various environmental factors (van Bergen et al, 2017). Apart from a long list of species, very little is known about the polyphenic butterflies of the Western Ghats (Halali et al, 2021;Molleman et al, 2020;. This work provides data on the relative seasonal proportions of numerous polyphenic butterfly species of the Western Ghats, and shows distinct distribution patterns of wet and dry season forms for a select few.…”

Let's wait for the evening: nocturnal copulation in a tropical damselfly Phylolestes ethelae (Odonata, Synlestidae)

“…3). Nocturnal copulation in mainly diurnal insects has been reported in some tropical regions, for instance in stalk-eyed flies (Lorch et al 1993) and butterflies (Molleman et al 2020), but appears to be a rare behaviour. Some temperate fruit flies show high variability in copulation duration, sometimes including the night (Rull et al 2017).…”

Larval growth rate affects wing shape more than eyespot size in the seasonally polyphenic butterflyMelanitis leda

“…Specifically, males tended to have even less falcate wings when they were wet-season forms than females. This indicates some subtle sexual dimorphism in wing shape in wet-season forms that may be connected to sex-biased movement patterns (Berwaerts et al 2002) or sexual selection (Kemp 2002; Molleman et al 2020a).…”