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D S Bertram

Publications and source records attributed to D S Bertram.

15 recordsLinked to original sources
PubMed1983

Experimental parasitization of eggs of Triatoma maculata (Erichson) by the oriental microhymenopteran, Gryon triatomae Masner and comment on the susceptibility of other neotropical triatomines.

The oriental microhymenopteran wasp, Gryon triatomae Masner, 1975 was reared in eggs of triatomine bugs, including vectors of Chagas' disease. In particular, G. triatomae was maintained for 31 generations in eggs of Triatoma maculata (Erichson). Only one parasite develops in each bug egg and 30 to 40 days are required for completion of development at 24 +/- 1 degrees C. Mean parasitization rate of 7484 eggs of T. maculata, in 54 rearings, was 34.7% with a range from zero to the highest rate of 86.7%. Mated females produce predominantly female progeny (mean sex ratio, 1 male:6.7 females). Unmated females produce parthenogenetic males. The wasp reproduces in fertile eggs, from those recently laid to those with well-advanced bug embryos. Infertile eggs are not usually parasitized. Both sexes survive for one to two weeks unfed, but for several weeks (up to 16 for females) if fed (on honey). Frequent ovipositions may reduce survival. Successful parasitization by females persisted for about three weeks but declined subsequently. Abortions of developing Gryon were usually 10% or less. Brief comparison with other neotropical triatomine species indicates that eggs of Triatoma spp. are susceptible to G. triatomae; Panstrongylus spp. seem relatively poor hosts, and there is little or no parasitization of Rhodnius spp.

Animals↗
PubMed1983

Parasitization by the microhymenopteran Gryon triatomae Masner of eggs of Triatoma maculata (Erichson) in holes and mazes of artificial walls.

Oriental parasitoid wasps, Gryon triatomae, were confined for several weeks in transparent tanks (400 X 180 X 200 mm) with eggs of the neotropical triatomine bug Triatoma maculata. The eggs were lodged in moulded holes (about 50 mm deep and 15 mm diameter) of polystyrene blocks, to simulate walls. The blocks were arranged with the holes either vertical or horizontal; openings of the holes were either 5 mm or 15 mm diameter. One wall included three mazes of linked holes, each maze with one entrance. Eggs were also accessible in an open petri-dish and on top of one wall. Some eggs in the walls and the maze block were in holes sealed off from access by wasps to provide controls, in order to assess fertility of the eggs, since this favours parasitization. This was satisfactory at 82.2% and 88.5% in two tanks studied. Parasitization rates were 32% of 50 eggs exposed to one female G. triatomae, with one male wasp, in one tank, and in the other 55.9% of 136 eggs exposed to 14 female wasps, with five males. In both tanks, eggs in the open petri-dish, in accessible vertical and horizontal holes and on top of walls were parasitized, but parasitization of eggs in the mazes occurred only in the tank with 14 female Gryon and then as far as the last, 18th, hole of the longest maze, a linear penetration by a searching wasp of about 270 mm; the distance travelled could be considerably greater. Late wasp oviposition after protracted questing may have caused the observed 15.8% abortion rate of G. triatomae. The few wasps seen by night were at rest, but at daybreak many more emerged from the walls and flew actively.(ABSTRACT TRUNCATED AT 250 WORDS)

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