A Reversible Color Polyphenism in American Peppered Moth (Biston betularia cognataria) Caterpillars

Insect body color polyphenisms enhance survival by producing crypsis in diverse backgrounds. While color polyphenisms are often indirectly induced by temperature, rearing density, or diet, insects can benefit from immediate crypsis if they evolve polyphenisms directly induced by exposure to the background color, hence immediately deriving protection from predation. Here, we examine such a directly induced color polyphenism in caterpillars of the geometrid peppered moth (Biston betularia). This larval color polyphenism is unrelated to the genetic polymorphism for melanic phenotypes in adult moths. B. betularia caterpillars are generalist feeders and develop body colors that closely match the brown or green twigs of their host plant. We expand on previous studies examining the proximal cues that stimulate color development. Under controlled rearing conditions, we manipulated diets and background reflectance, using both natural and artificial twigs, and show that visual experience has a much stronger effect than does diet in promoting precise color matching. Their induced body color was not a simple response to reflectance or light intensity but instead specifically matched the wavelength of light to which they were exposed. We also show that the potential to change color is retained until the final (sixth) larval instar. Given their broad host range, this directly induced color polyphenism likely provides the caterpillars with strong protection from bird predation

Bionomy of Anicla mahalpa Schaus, 1898 (Lepidoptera: Noctuidae: Noctuinae), in the laboratory

The genus Anicla Grote, 1874 is composed of eleven species; their larvae are harmful, mainly to native and cultivated grasses, but up to now, there is information available of only two species. This study aims at detailing the bionomy of A. mahalpa Schaus; the data were obtained from a laboratory rearing under the following settings: 20 ± 2 ºC, 70 ± 10% relative humidity and 12 hours of photoperiod. Larvae were fed on ryegrass, Lolium multiflorum Lam. (Poaceae). The results expressed by the mean and respective standard error for the periods of each phase, in days, were the following: egg 6.00 ± 0.00, larva 36.47 ± 0.44, pre-pupa 5.23 ± 0.21, pupa 23.60 ± 0.37, and adult: longevity 15.24 ± 0.75 with pre-egg-laying-periods of 5.29 ± 0.32; egg-laying period, 9.64 ± 0.81, and post-egg-laying period, 0.71 ± 0.27 days. The mean number of egg-laying cycles per female was 7.36 ± 0.20 and 2,014.21 ± 78.93 eggs per female. Eggs, which are subspheric, have a diameter of 0.76 ± 0.01 mm; larvae passed through six instars; their head capsules width, provided a mean ratio of growth of 1.482. Pupae presented a mean width and length of 6.07 ± 0.06 and 17.24 ± 0.19 mm, respectively and weight of 0.33 ± 0.01 g