Toshiyuki Nishida

Comparative Demography of Three Hawaiian Fruit Flies (Diptera: Tephritidae) at Alternating Temperatures

Abstract Reproductive and population parameters of melon flies, Bactrocera cucurbitae Coquillett, oriental fruit flies, B. dorsalis Hendel, and Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were measured in environmental chambers maintained at temperatures of (maximum:minimum) 24:13, 24:24, 29:18, and 35:24 ± 1°C. Alternating temperature regimes more realistically approached the variation found in nature and produced higher parameters than an optimal constant temperature (24°C). Intra- and interspecific comparisons were done with 4 separate generations of wild fruit flies reared on a common natural host. All species attained their highest intrinsic rates of population increase at 29:18 or 35:24°C; C. capitata exhibited the highest intrinsic rates of increase at all temperature regimes. All species attained maximum net reproductive rates at 29:18°C, in the order C. capitata > B. dorsalis > B. cucurbitae. The 35:24°C regime caused reductions in net reproductive rates of all species, with B. dorsalis affected most strongly. Male longevity was greater than that of females for all species in all temperature regimes. Two distinctly different life history patterns were evident: (1) early reproduction, short life span, and a high intrinsic rate of increase (C. capitata), and (2) later onset of reproduction, longer life span, and a lower intrinsic rate of increase (B. cucurbitae).

Behavior and mortality of the southern stink bugNezara viridula in Hawaii

This paper is concerned with some aspects of the ecology of the southern green stink bug,Nezara viridula, in Hawaii. Dispersal studies on adults showed an asymetrical dispersal pattern. The rate of plant to plant to movement by the adults was 3.3–6.7 feet per day. Mortality studies showed that egg predation by ants,Pheidole megancephala, was as high as 80–90 per cent. Egg parasitism byTelenomus basalis was highest during February, 1965, and adult parasitism byTrichopoda pennipes was highest during July, 1964, to January of the following year. The population ofN. viridula declined during May, 1964, to May, 1965. This decline occurred simultaneously with the decline in the number of eggs produced per female. It has been speculated that this reduction in egg production was caused by parasitism byT. pennipes.