Behavioural, ecological and genetic evidence confirm the occurrence of host-associated differentiation in goldenrod gall-midges.
Host-associated differentiation (HAD) is considered a step towards ecological speciation and an important mechanism promoting diversification in phytophagous insects. Although the number of documented cases of HAD is increasing, these still represent only a small fraction of species and feeding guilds among phytophagous insects, and most reports are based on a single type of evidence. Here we employ a comprehensive approach to present behavioural, morphological, ecological and genetic evidence for the occurrence of HAD in the gall midge Dasineura folliculi (Diptera: Cecidomyiidae) on two sympatric species of goldenrods (Solidago rugosa and S. gigantea). Controlled experiments revealed assortative mating and strong oviposition fidelity for the natal-host species. Analysis of mitochondrial DNA showed an amount of genetic divergence between the two host-associated populations compatible with cryptic species rather than host races. Lower levels of within-host genetic divergence, gall development and natural-enemy attack in the S. gigantea population suggest this is the derived host.
Dorchin
N
N
Department of Biology, Bucknell University, Lewisburg, PA, USA. n.dorchin.zfmk@uni-bonn.de
Scott
E R
ER
Clarkin
C E
CE
Luongo
M P
MP
Jordan
S
S
Abrahamson
W G
WG
D000818:Animals; D004175:Diptera / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D005260:Female; D006790:Host-Parasite Interactions / Q000502:physiology*; D007814:Larva / Q000502:physiology; D008297:Male; D010058:Oviposition / Q000502:physiology; D010802:Phylogeny; D012726:Sexual Behavior, Animal / Q000502:physiology*; D036624:Solidago / Q000469:parasitology*