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The Effects of Thermal Heterogeneity in the Environment on the Activity and Development of Oncopeltus Fasciatus (Dallas)
Author(s) -
Barrett Ronald W.,
Chiang H. C.
Publication year - 1967
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1936503
Subject(s) - nymph , morning , period (music) , biology , ecdysis , ecology , abundance (ecology) , instar , zoology , botany , larva , physics , acoustics
The reactions of age specific nymphs of the milkweed bug to a heat spot in the laboratory and to sunlight in the field were observed. Laboratory results showed that in an environment where a thermal heterogeneity is present, the insects were attracted to a spot warmer than the ambient temperature. This was particularly striking when the ambient temperature was low, as reflected by both the large percent of nymphs which responded and by a higher chosen temperature. The responses also varied with the intra—instar age, being the most striking in the pre—feeding period, next in the post—feeding period, and the least in the feeding period. Ecdysis, however, never occurred on the heat spot even at low ambient temperatures. Heat spot aggregation resulted in a higher rate of development. This increment was greater at lower ambient temperatures. These results correlated with the field observations. During the pre—feeding period, the nymphs stayed on the top parts of plants basking in the sun throughout the day. During the feeding period and post—feeding period, they stayed in the sun only during the morning hours. The possible implications of these activity patterns to the survival, abundance and distribution of the species also are discussed.