Sceliphron

Abstract: Two female Thraxan sp. (Diptera: Bombyliidae: Anthracinae) emerged from parasitised Pison simillimum Smith (Hymenoptera: Crabronidae) larvae found inside a Sceliphron formosum Smith (Hymenoptera: Sphecidae) mud wasps nest. Thraxan sp. larvae are endoparasites of P. simillimum larvae. The endoparasite pupates inside the host larva, kills it, and emerges free of the host body. We describe and illustrate the pupal exuviae of the newly found species and two known species, T. luteus Yeates & Lambkin and T. misatulus Yeates & Lambkin, and we compare these pupal exuviae to those of Anthrax Scopoli.

Abstract: Three new species are added to the genus Epipompilus (Hymenoptera: Pompilidae) in Australia. Epipompilus mirabundus sp. nov., E. taree sp. nov., and E. namadgi sp. nov. are described and illustrated. A key to males of Epipompilus is provided. A novel association of Epipompilus and Sceliphron formosum (Hymenoptera: Sphecidae) is also documented. The larva of E. mirabundus sp. nov. was found sharing single nest cell with a Sceliphron larva; this association could be the result of a parasitised spider being brought back to the nest by the Sceliphron adult.

Abstract: In the small carpenter bee, Ceratina calcarata (Robertson), female eggs are laid on provision masses that are larger than those that receive male eggs. Because there is a positive relationship between the size of the adult and the amount of food available to it as a larva, the females are larger than the males. Large size in female insects is often associated with an increase in fecundity. However, it was determined that in C. calcarata, there was no correlation between the size of the mother and either the number of brood cells in her nest or the number of eggs she laid. There was a positive correlation between a mother's size and her foraging ability judging by the size of the provision masses she stored. But larger mothers did not produce more daughters than sons as might be expected. The question of the advantage to C. calcarata mothers of making daughters larger than sons is considered. An increase in fecundity is often associated with an increase in the size or weight of a female insect (e.g., Leather and Wellings, 1981; Juliano, 1985; Leather, 1988) and this pattern is generally true for nonsocial Hymenoptera. The parasitoid, Nasonia vitripennis, shows a positive correlation between the female's body size and the number of progeny produced (Saunders, 1966). In the eumenid wasps Ancistrocerus adiabatus and Euodynerus foraminatus, Cowan (1981) found that larger females "provisioned more cells (and thus laid more eggs) than smaller females." Freeman (1981) noted a similar situation in the sphecid Sceliphron assimile. Wilmer (1985) found in another sphecid, Cerceris arenaria, that larger females had as much as twice the egg-laying success as did smaller females. However, a similar relationship between female size and fecundity was not found in the twig-nesting solitary bee Osmia lignaria propinqua (Tepedino and Torchio, 1982). They reported no correlation between female size and the number of nests produced, the number of brood cells produced, the total number of offspring produced or the number of offspring that survived. In the small twig-nesting anthophorid carpenter bee, Ceratina calcarata (Rob ertson), the female is the larger sex. The size of the adult is positively related to the amount of food it received as a larva (Johnson, 1988). Therefore, the mother must do more work (i.e., harvest more food) to produce a female offspring than to produce a male one. Thus it seems reasonable to assume that larger size is more advantageous to female offspring than to male offspring. If there is a relationship between female size and fecundity in C. calcarata then a larger female should produce more brood cells in her nest (and thus lay more eggs) than a smaller female. Furthermore, if larger females are more efficient at collecting food (Cowan, 1981; Freeman, 1981) they might also produce larger provision masses and hence larger offspring. Since females are produced on rel Accepted for publication 11 December 1989. This content downloaded from 40.77.167.44 on Fri, 10 Jun 2016 06:34:41 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 3 415 atively larger provision masses, this leads to the further possibility that the larger mothers might produce proportionally more female offspring than do smaller mothers (Fisher, 1958; Trivers and Hare, 1976). In this research, an effort was made to determine if there is a relationship between mother size and the number and sex of offspring in the nests of C calcarata. Materials and Methods C. calcarata nests used were collected in Indiana (Putnam Co.) from the woody twigs of multifloral rose (Rosa multiflora) and raspberry (Rubus sp.) during the nesting periods (late May to early July) of 1983-1985, 1987-1988. In 1985, 1987 and 1988, active nests were marked and left in the field until nesting was completed (estimated from observations of other nests opened during that nesting period). Nests were collected in the early evening so that the resident female, assumed to be the mother, could be associated with her nest. Nests were split open lengthwise in the lab and the nest contents removed. The immatures were reared as described in Johnson (1988). The mother was weighed (live) using a Mettler analytical balance (?0.001 g). The mother and her offspring were preserved together in alcohol. In all, 20 completed nests (1 from 1985, 10 from 1987 and 9 from 1988) were collected with their mothers. A nest was considered complete if the egg in the outermost brood cell (the last one produced) had hatched and was a feeding larva. This means that it was at least 5 days since the last brood cell was provisioned.