LE3 .A278 2013

2013

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Pine engraver beetles, Ips pini Say, 1826 (Coleoptera: Curculionidae), are widely distributed across Canada, and invade several species of Pinus Linnaeus (Pinaceae), where they complete their life cycle under the outer bark, in the phloem. Acoustic communication confers many advantages to insects, and is used in avoiding predation, courtship and mating, marking territory, and facilitating social interactions. It has long been known that female pine engraver beetles produce signals using a vertex-pronotum stridulatory mechanism, but the mechanism by which these signals are received has not yet been described. The first objective of this study was to examine the potential role of the antennal pedicel as an acoustic receptor in pine engraver beetles. The second objective was to describe how stridulation varied over the course of a male-female interaction, by comparing interpulse intervals of signals recorded from a microphone and accelerometer-based sensor. Significant differences were not found in any of eight parameters of antennal size among 10 males and 10 females. The pedicel of the antenna does not appear to be enlarged to contain chordotonal organs for acoustic reception. Interpulse intervals prior to female entry into the nuptial chamber were most commonly between 0.4-0.7 ms, whereas post-entry interpulse intervals were 0.1 ms. Over a six-week period, interpulse intervals were most commonly 0.1 ms. These data suggest that although interpulse intervals may not vary much within the introduction of a female, they do differ between the introduction and post-entry. The accelerometer-based sensor is a useful tool for detecting beetle activity as these insects burrow beneath the phloem into the nuptial chamber and egg gallery, and can be used in further long term analysis of male-female interactions in the phloem.

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https://scholar.acadiau.ca/islandora/object/theses:1049