Group size effects on survivorship and adult development in the gregarious larvae of Euselasia chrysippe (Lepidoptera, Riodinidae)

Abstract

Caterpillars living in aggregations may derive several benefits that outweigh the costs, including better survivorship and improved growth rates. I tested whether larval group size had an effect on these two vital rates in Euselasia chrysippe. These caterpillars feed gregariously during all instars and move in processionary form over the host plant and even pupate together. There was a positive relationship between group size and larval survivorship in the field, although genetic variability was not taken into account in this experiment. Under laboratory conditions, there was also a positive relationship between group size, and larval growth rate and adult weight. This supports the hypothesis that aggregations facilitate feeding and larval growth. Single sixth instar larvae in the laboratory also had a lower survivorship than larvae in groups. These results provide further evidence of the benefits of group living for gregarious caterpillars.

Differential physiological responses of the German cockroach to social interactions during the ovarian cycle

“…Moreover, in some insect species, reproduction can be accelerated in females by the presence of individuals of various developmental stages, both genders, and even different species (e.g. Lees, 1967;Bradley, 1985) (reviewed in Braendle et al, 2006;Allen, 2010).…”

Damage toMiconia calvescensand Seasonal Abundance ofSalbia lotanalis(Lepidoptera: Crambidae) in Costa Rica

“…On each of the 10 randomly selected trees, the total number leaves with and without leaf rolling were counted in November 2006, March 2007, and September 2012. November and March were chosen because they correspond to the approximate endpoints of the rainy and dry seasons, respectively, which we previously had observed to markedly affect growth and leaf drop of M. calvescens in this habitat (Allen 2010). Plants were resampled 5 yr later in September 2012 to see if S. lotanalis continued to impact this site.…”

Arge xanthogaster(Hymenoptera: Argidae): A New Threat to Rose Plants in Meghalaya, India

“…These characteristics could aid in avoiding increased risk of predation and parasitism, which, occurs comparatively more frequently under solitary conditions (Costa 1997;). In addition, gregariousness also improves resource localization and assimilation (Bryant et al 2000;Fordyce 2003), better survivorship and improved growth rate (Allen 2010). In addition to this, a slight disturbance to A. xanthogaster larvae results in them curling their posterior body (in a snake-like manner), which may reinforce the effectiveness of the pubescence by producing a 'hedgehog effect'.…”