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The calling behaviour and spatial distribution of male bushcrickets (Sciarasaga quadrata) and their relationship to parasitism by acoustically orienting tachinid flies


Allen, GR, The calling behaviour and spatial distribution of male bushcrickets (Sciarasaga quadrata) and their relationship to parasitism by acoustically orienting tachinid flies, Ecological Entomology, 20, (4) pp. 303-310. ISSN 0307-6946 (1995) [Refereed Article]

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DOI: doi:10.1111/j.1365-2311.1995.tb00461.x


1. This paper examines the calling behaviour and spatial distribution of male Sciarasaga quadrata Rentz (Orthoptera: Tettigoniidae), a bushcricket that is subject to attack by an acoustically orienting parasitoid fly, Homotrixa sp. (Diptera: Tachinidae: Ormiini).
2. Checks on calling activity in populations of S.quadrata confirmed that calling began 23 h before sunset and continued well beyond midnight. Calling activity was not restricted by temperature with males calling over air temperatures of 10.624.2C.
3. Nearest-neighbour analyses, within the sampled areas, revealed that the spacing between calling males was random and the minimum distance between calling males was 3.74 m. Mean distances between calling males varied between 9.2 m and 23.0 m and significantly changed as male density, which peaked at 0.36 calling males per 100 m2, declined over the calling season.
4. Males showed no preference for any one plant species, with their distribution across bushes not significantly different to the frequency of the plants within the habitat. The perch height of calling males was on average half way up the height of a bush and was significantly influenced by the height of the bush. Perch height was not significantly influenced by proximity to calling males or by whether or not males were parasitized.
5. Site fidelity of males was low with only 010% of bushes occupied by calling males over successive nights. Males, though flightless, moved on average 6.70 m and up to 26.56 m per night.
6. No evidence was found for the use of aggregation in S.quadrata as a primary defence against ormiine attack. Commencing calling prior to sunset, frequent movement, and a lack of association with any particular plant species, although possibly relevant to ormiine attack, could also be explained in terms of other activities such as male-male interactions and mating behaviour.

Item Details

Item Type:Refereed Article
Keywords:Sciarasaga quadrata, Tettigoniidae, Homotrixa sp., Ormiini, Tachinidae, parasitoid, spatial distribution, acoustic signalling
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Allen, GR (Associate Professor Geoff Allen)
ID Code:102682
Year Published:1995
Web of Science® Times Cited:24
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2015-09-03
Last Modified:2015-10-06

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