Volume 57, Issue 1 pp. 168-172
Free Access

ONE HOST SHIFT LEADS TO ANOTHER? EVIDENCE OF HOST-RACE FORMATION IN A PREDACEOUS GALL-BORING BEETLE

MICKY D. EUBANKS

MICKY D. EUBANKS

Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, Alabama 36849 E-mail: [email protected]

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CATHERINE P. BLAIR

CATHERINE P. BLAIR

Department of Biology, Bucknell University, Lewisburg, Pennsylvania 17837

Department of Biology, Bucknell University, Lewisburg, Pennsylvania 17837. E-mail: [email protected]

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WARREN G. ABRAHAMSON

WARREN G. ABRAHAMSON

Department of Biology, Bucknell University, Lewisburg, Pennsylvania 17837

Department of Biology, Bucknell University, Lewisburg, Pennsylvania 17837. E-mail: [email protected]

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First published: 09 May 2007
Citations: 53

Abstract

Abstract.— We show that a predator, the tumbling flower beetle Mordellistena convicta (Coleoptera: Mordellidae), has formed host races in response to a host-plant shift and subsequent host-race formation by its prey, the gall-inducing fly Eurosta solidaginis (Diptera: Tephritidae). This fly has formed two host races, one that induces stem galls on the ancestral host plant, Solidago altissima (Compositae), and another that induces stem galls on the closely related S. gigantea. We found that subpopulations of M. convicta that attack E. solidaginis galls on the different host plants have significantly different emergence times and, although slight, these allochronic differences are consistent across a range of temperatures. More importantly, we found that beetles assortatively mate according to their natal host plants, and female M. convicta preferentially attack and/or their offspring have higher survival in galls on natal host plants. Our data suggest that subpopulations of M. convicta that attack E. solidaginis galls on S. altissima and S. gigantea have formed host races. This is one of the first studies to demonstrate that a host shift and subsequent host-race formation by an herbivorous insect may have resulted in subsequent diversification by one of its natural enemies.

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