Behavior Changes the Reproduction of Spalangia cameroni, S. endius, Muscidifurax raptor, and Nasonia vitripennis (Hymenoptera: Pteromalidae) at Increasing Fly Host Densities1

Dinâmica populacional e parasitismo de Himenópteros parasitóides de Chrysomya megacephala (Fabricius) (Diptera, Calliphoridae), no Rio de Janeiro, RJ

“…Por sua vez, Olton & Legner (1974) não encontraram relação entre o número de hospedeiros parasitados por este Encyrtidae e a densidade de moscas. Estes resultados contrariam Legner (1967), segundo o qual, a maioria dos parasitóides tem sua habilidade de reproduzir ligada ao aumento da densidade hospedeira, limitada evidentemente, pela capacidade reprodutiva de cada espécie.…”

Studies of four thelytokous puerto rican isolates ofMuscidifurax uniraptor [Hymenoptera: Pteromalidae]

“…Each 9 was supplied daily with 20 24-to 30-h-old puparia of M. domestica L., 6.4 +_ 0.5 mm • 2.8 + 0.2 mm, distributed randomly over the vial base, the larvae of which had been reared on commercial CSMA R medium. Parasitization efficiency at this host density and in this environment at 25.5 ~ was near the asymptote (Legner, 1967 ;1979).…”

Studies on the bionomics ofTrioxys (Binodoxys) indicus [Hym.: Aphidiidae]: Effect of population densities on sex ratio

“…FLANDERS (1967) also stated that the sex differentiation is also brought about by the differential placement of haploid and diploid eggs which is a directly psychological process activated either by mating or indirectly by the availability of host. The haploid eggs are placed on (in) unpreferred hosts while diploid eggs are deposited on (in) preferred ones (FLANDERS, 1939;LEGNER, 1967). Host preferrence by the parasitoid is influenced by the age, size, shape and condition (parasitized, probed or touched by the parasitoid) of the hosts (VINsoN, 1976).…”

“…However, during the present investigation aphids have not been observed to be dropped by the movements of either of the parasitoid sexes either "in the field or in the laboratory. Although the interrelationships between the sex ratio and the population density of hosts and their chalcid parasitoids have been studied (FLANDERS, 1946;KING, 1961;WYLIE, 1966aWYLIE, , 1966bLEGNER, 1967;ABDELRAHMAN, 1974;ASKEW & RUSE, 1974), but little information is available on aphids and their aphidiid parasitoids (WIACKOWSKI, 1962;MACKAUER, 1969MACKAUER, , 1976aMACKAUER, , 1976b. MACKAUER (1976a) studied the effect of post copulatory period on the sex ratio of Aphidius smithi SHARMA & SURBA RAO and suggests the existence of some sort of regulatory mechanism which ensures the production of males by the mated females for the fertilization of females of next generation.…”