Dynamics of growth modified by larval population density in the flesh fly, Sarcophaga bullata

Abstract

1983. Dynamics of growth modified by larval population density in the flesh fly, Sarcophaga bullata. Can. J. Zool. 61: 5 12-5 17. Growth functions were fitted to the growth curves of larvae of the flesh fly, Sarcophaga bullata Parker (Diptera: Sarcophagidae), reared in conditions that were either uncrowded (25 larvae per 25 g beef liver) or crowded (400 larvae per 25 g beef liver). The growth curves took the form of logistic functions that were symmetrical for uncrowded larvae, but asymmetrical for crowded ones. Initially, crowded larvae grow faster than uncrowded larvae, a response in contrast with those of all other species of higher Diptera studied to date. Apparently, crowded larvae derived benefit from close intraspecific associations, for their rapid growth took place while they fed within dense aggregations. The growth rate of crowded larvae peaked early and growth ceased abruptly when the supply of food was exhausted. Their feeding period was reduced by 60% and their weight by 74% in comparison with those of uncrowded larvae. BAXTER, J. A., et P. E. MORRISON. 1983. Dynamics of growth modified by larval population density in the flesh fly, Sarcophaga bullata. Can. J. Zool. 61: 5 12-5 17.Les tquations des courbes de croissance des larves de la mouche ii viande Sarcophaga bullata Parker (Diptera: Sarcophagidae) ont Ct C calculCes dans le cas de larves ClevCes dans des conditions de densit6 faible (25 larves sur 25 g foie de boeuf) ou de densit6 ClevCe (400 larves sur 25 g foie de boeuf). Les courbes de croissance prennent la forme de fonctions logistiques symktriques dans le cas des larves ClevCes ii densit6 faible et asymktriques dans le cas de larves ClevCes ii densit6 forte. Au dCbut, les larves 21 densit6 ClevCe ont une croissance plus rapide que les larves ii densit6 faible, ii l'inverse de toutes les autres espkces de Diptkres supkrieurs ClevCs ii ce jour. Les larves ClevCes dans les conditions de densit6 ClevCe semblent bCnCficier des associations intrasptcifiques Ctroites, puisque leur croissance est rapide lorsqu'elles se nourrissent au sein de rassemblements importants. Le taux de croissance des larves 21 forte densit6 a atteint un palier assez rapidement et la croissance a cesd brusquement a 1'Cpuisement des ressources alimentaires. Leur pCriode d'alimentation s'est trouvCe rCduite de 60% et leur masse de 74% comparativement aux larves ClevCes ii une faible densitC.[Traduit par le journal]

Parasitism of the grasshopper Melanoplus sanguinipes by a sarcophagid fly, Blaesoxipha atlanis: influence of solitary and gregarious development on host and parasitoid

“…Solitary larvae developed for longer, and were on average larger as adults, than counterparts developing gregariously (Table 3). A decrease in development time with an increase in parasitoid load was also observed in a braconid wasp (Beckage & Riddiford, 1978 and in several non-parasitic sarcophagid flies (Baxter & Morrison, 1983;So & Dudgeon, 1989). The decline in body size was especially pronounced in cases of three larvae developing gregariously in male grasshoppers.…”

“…Gregarious development incurred a fitness cost due to the positive correlation between body size and fecundity in females (Figures 1 and 2) and, possibly also, in males. A reduction in body size and fecundity as a result of competition between gregarious larvae is a common phenomenon in parasitic sarcophagids (Coupland & Baker, 1994) and tachinids (King et al, 1976;Grenier, 1981), non-parasitic sarcophagids (Baxter & Morrison, 1983;So & Dudgeon, 1989;Tanaka et al, 1990), and hymenopteran parasitoids (Rojas-Rousse et al, 1988;Taylor, 1988;Reitz & Adler, 1995).…”

“…Although little is known about gregarious development in sarcophagid parasitoids, research on non-parasitic species has shown that resources are utilized during larval development, apparently, by exploitative competition in a manner similar to that observed in gregarious parasitoid wasps. For example, increased densities of larvae in rearing media resulted in shorter developmental time and lower mean larval dry mass in Sarcophaga bullata Parker (Baxter & Morrison, 1983), reduced dry mass of puparia in Pecia abnormalis Enderlein (Tanaka et al, 1990), and lower survivorship, developmental time, dry mass, and fecundity in Boettcherisca formosensis Kiner & Lopes (So & Dudgeon, 1989).…”

Larval aggregation and competition for food in experimental populations of Chrysomya putoria (Wied.) and Cochliomyia macellaria (F.) (Dipt., Calliphoridae)

“…The aggregation of larvae in masses ensures a plentiful supply of secretions for the pre‐digestion of the food resources, but group oviposition may lead to ‘too many’ eggs laid on some carcasses ( Kuusela 1984). Where larvae are crowded out or they become isolated or in small groups, undercrowding will occur, and therefore single larvae are unable to produce enough digestive fluid to obtain sufficient food by themselves ( Mackerras 1933 ; Ullyett 1950; Baxter 1983) .…”

Aspectos bionômicos de Squamatoides trivittatus (Diptera, Sarcophagidae) sob condições de laboratório

“…Em sua maioria, os trabalhos relacionados com as fases imaturas avaliam o perío-do de desenvolvimento, a viabilidade e a competição larval em diversas condições de temperatura e umidade relativa (Kamal 1958, House 1977, Levot et al 1979, Baxter & Morrison 1983Jirón & Bolanos 1986, Ferraz 1992a. Os artigos relacionados à fase adulta estão em grande parte relacionados aos aspectos comportamentais (preferên-cia de substrato para postura e alimentação), biogeográficos (sinantropia), longevidade e capacidade reprodutiva (Kamal 1958, Ferreira 1978, Linhares 1979, 1981, d'Almeida 1983, 1984, 1988, 1989, 1993, Ferraz 1992a.…”