Competição larval em Chrysomya megacephala (F.) (Diptera: Calliphoridae): efeitos de diferentes níveis de agregação larval sobre estimativas de peso, fecundidade e investimento reprodutivo

Abstract

Larval competition in Chrysomya megacephala (F.) (Diptera: Calliphoridae): effects of different levels of larval aggregation on estimates of weight, fecundity and reproductive investmentIn insects that utilize patchy and ephemeral resources for feeding and egg laying, the outcome of larval competition for food resources depends on the amount of resources and the spatial distribution of immatures among patches of food. In the present study, the results of larval competition for food in Chrysomya megacephala, in traits such as female weight, fecundity and reproductive investment, were different in situations where the level of larval aggregation (proportion of competitors per amount of food) was the same, but with densities of competitors and amounts of food proportionally different. These results are indicative that the larval competition may depend both on the larval density and the amount of food, in different situations with the same proportion of larvae per gram of food.Key words: Chrysomya megacephala, fecundity, female weight, larval aggregation, reproductive investment. RESUMOEm insetos que se utilizam de substratos discretos e efêmeros para a alimentação e postura de ovos, o resultado da competição larval por alimento depende da quantidade de recursos e da distribuição espacial dos imaturos nos substratos alimentares. No presente estudo, os resultados da competição larval por alimento em Chrysomya megacephala, em caracteres como peso de fêmeas, fecundidade e investimento reprodutivo, foram diferentes em situações em que o nível de agregação larval (proporção de competidores por quantidade de alimento) é o mesmo, mas com densidades de competidores e quantidades de alimento proporcionalmente diferentes. Esses resultados indicam que a competição larval pode depender tanto da densidade larval como da quantidade de alimento, em situações diferentes com a mesma proporção de larvas por grama de alimento.Palavras-chave: Chrysomya megacephala, fecundidade, peso de fêmeas, agregação larval, investimento reprodutivo.

Alternative Diets forChrysomya putoria, an Old World Screwworm Fly

“…The larval viability rate in the gizzard homogenate diet was 73% (60 g of diet for 40 larvae = 1.5 g of diet per larva), presenting a similar rate to that reported by Godoy et al (1996), who used an artificial diet, and the rate reported by Leal et al (1982), of 73.25% at a density of 50 g of diet for 100 larvae (0.5 g of diet per larva) and at the 20 other densities tested with smaller quantities of diets fed to larvae. The diet used by Leal et al (1982) has been used by several other authors (Von Zuben et al 2000; Estrada et al 2009), and the achievement of a similar viability indicates a good result.…”

Prey choice by facultative predator larvae of Chrysomya albiceps (Diptera: Calliphoridae)

“…Interspecific interactions in blowfly system have been investigated in experiments in which population dynamics and competitive ability of the invading species C. rufiffacies and C. albiceps, and of the native species C. macellaria were analyzed (Wells & Greenberg 1992a,b,c, 1994, Wells & Kurahashi 1997, Faria et al 1999, Reis et al 1999, Von Zuben et al 2000. These investigations were attempts to gain a deeper understanding of recent blowfly biological invasion in Americas and its implications on population dynamics.…”

Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) Oviposition Behavior in Previous Oviposition Situation

“…On the other hand, high levels of larval aggregation may cause unfavorable conditions for the maggots (Rivers et al 2011) such as negative influence on adult female fertility and reproductive investment, maggot size on final stages of development, and weight of the resulting adults (Kamal 1958, Levot et al 1979, Von Zuben et al 2000, Ireland & Turner 2006, Reigada & Godoy 2006. Goodbrod & Goff (1990) showed that the optimal larval density for C. megacephala is 8 larvae/g of the substrate.…”