ARS | Publication request: Coexistence and competition between Tomicus Yunnanensis and T. minor (Coleoptera: Scolytidae) in yunnan pine

Submitted to: Psyche
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2011
Publication Date: December 12, 2011
Citation: Lu, R.C., Wang, H.B., Zhang, Z., Byers, J.A., Jin, Y.J., Wen, H.F. 2012. Coexistence and competition between Tomicus Yunnanensis and T. minor (Coleoptera: Scolytidae) in yunnan pine. Psyche. vol.2012,pp.1-6.

Interpretive Summary: We studied the competition and cooperation between two species of pest bark beetle, Tomicus yunnanensis and Tomicus minor (Coleoptera: Scolytidae) when they live together in Yunnan pine trees (Pinus yunnanensis L.) growing in Yunnan province in southwest China. We observed that T. yunnanensis beetles begin to disperse from shoots to trunks in November while most T. minor begin to transfer in December. T. yunnanensis mainly attacks the top and middle part of the trunk, whereas T. minor resides mostly in the lower and middle part of the trunk. The highest attack densities of these two species showed a similar pattern, with T. yunnanensis colonizing the upper section of the trunk and T. minor in the lower trunk. The highest attack density of T. Yunnanensis was about 297 egg galleries/m2, and the highest attack density of T. minor was about 305 egg galleries/m2. The two species colonize different areas of the tree, but with significant overlap for the same bark resource, and thus these behaviors reduce the intensity of competition for the relatively thin layer of phloem-cambium tissues.

Technical Abstract: Competition and cooperation between bark beetles, Tomicus yunnanensis and Tomicus minor (Coleoptera: Scolytidae) were examined when they coexisted together in living Yunnan pine trees (Pinus yunnanensis L.) in Yunnan province in southwest China. T. yunnanensis bark beetles were observed to initiate dispersal from pine shoots to trunks in November; while the majority of T. minor begins to transfer in December. T. yunnanensis mainly attacks the top and middle parts of the trunk, whereas T. minor mainly resides in the lower and middle parts of the trunk. The patterns of attack densities of these two species were similar, with T. yunnanensis colonizing the upper section of the trunk and T. minor the lower trunk. The highest attack density of T. Yunnanensis was 297 egg galleries/m2, and the highest attack density of T. minor was 305 egg galleries/m2. Although there was significant overlap for the same bark areas, the two species generally colonize different areas of the tree, which reduces the intensity of competition for the relatively thin layer of phloem-cambium tissues.