Potential and realised fecundity in the bush fly, Musca vetustissima under favourable and unfavourable protein‐feeding regimes

Abstract

The number of ovarioles in female Musca vetustissima (potential fecundity/ovarian cycle) is positively correlated with fly size (headwidth) and potential fecundity does not vary between successive ovarian cycles. Field females of average headwidth (2 mm) have a mean potential fecundity of 25 eggs/cycle. Females are anautogenous, needing to ingest protein‐rich material in order to mature their oocytes. Females that obtain insufficient protein material for maturation of full egg complements may cease ovarian development before or during early vitellogenesis, or resorb some of their oocytes and mature the remainder. Field females consistently matured in excess of 85% of their egg complements, indicating that female M. vetustissima have ready access to protein‐rich material in the field. Résumé Fécondités potentielle et réelle de Musca vetustissima avec des régimes protéiques convenable ou insuffisant Le nombre d'ovarioles des Musca vetustissima femelles (fécondité potentielle/cycle ovarien) est lié directement à la taille de la mouche (largeur de la tête); la fécondité potentielle ne varie pas entre les cycles ovariens successifs. Les femelles de la nature, d'une largeur de tête moyenne (2 mm) ont une fécondité potentielle moyenne de 25 oeufs par cycle. Les femelles anautogènes, ont besoin d'un repas riche en protéines pour produire des oeufs mürs. Les femelles qui n'obtiennent pas la quantité suffisante de protéines pour permettre la maturation d'un lot complet d'oeufs peuvent interrompre leur développement avant ou pendant le début de la vitellogenèse, ou résorber certains ovocytes tout en conduisant à maturité le reste. Les femelles de la nature conduisent a maturité 85% de leurs lots d'oeufs, montrant ainsi que les femelles de M. vetustissima y ont un accès facile à des aliments riches en protéines.

Influences of temperature, fly size and protein‐feeding regime on ovarian development rates in the Australian bush fly, Musca vetustissima

“…These females had similar access (48 h) to protein to that of females at 19~ in the experiments reported here and also developed at similar rates. However, the latter females not only developed their ovaries more slowly than expected, but also matured much reduced egg complements (Table 2), which is indicative of an inadequate protein intake during early development (Vogt & Walker, 1987). It seems likely therefore that female M. vetustissima require access to protein-rich material for longer periods at temperatures below 20~ in order to mature their full egg complements at the expected (maximal rates).…”

“…However, substantial delays were evident during egg stages 1 and 2, and females matured only 38.9~ of their egg complements. In M. vetustissima, maturation of reduced egg complements is associated with oocyte resorption (Vogt & Walker, 1987), which in most females is initiated during egg stage 3 when follicles have attained a mean length of 1.15 mm (yolk length/follicle length ratio = 0.43, Fig. 2).…”

“…Then, field females are assumed to mature their ovaries at maximal rates that are determined solely by tern-perature. However female M. vetustissima need access to protein-rich material for oocyte maturation, and field females may not always obtain sufficient protein to mature their full egg complements, in which case they resorb some oocytes and mature the remainder (Vogt & Walker, 1987). Since suboptimal protein-feeding has been shown to retard ovarian development in two other anautogenous species, the Australian sheep blowfly, Lucilia cuprina (Vogt et al, 1985b) and the face fly, Musca autumnalis (van Geem & Broce, 1985), female M. vetustissima may not mature their ovaries at maximal rates in the field.…”

On the population dynamics of the Australian bushfly

“…24. Reduced availability of protein in the environment, which has been shown to reduce the size of the egg complement (Vogt and Walker 1987), would also effectively lower the value of α l and, hence, the value of α. By quantifying this reduction in the value of α, it may be possible to investigate the effectiveness of eradication strategies.…”

Attraction of Scavenging Chloropid and Milichiid Flies (Diptera) to Metathoracic Scent Gland Compounds of Plant Bugs (Heteroptera: Miridae)

“…Anautogeny, the requirement for a meal of blood or proteinaceous food to produce eggs, is known for species in several other dipteran families, including Muscidae, Calliphoridae, Simuliidae, Psychodidae, Ceratopogonidae, Tabanidae, and Tephritidae (Leprince and Lewis 1983, Magnarelli et al 1984, Vogt and Walker 1987, Adams and Nelson 1990. Mean EAG responses of O. trigramma female antennae to C 4 ÐC 6 butyrates.…”