In 1996, investigations started on the agromyzid fly Napomyza sp. near lateralis as part of a biological control project against scentless chamomile (Tripleurospermum perforatum). One year later, the ‘same’ species was discovered on Russian knapweed (Acroptilon repens), also a target for biological control. Host-specificity tests revealed that specimens from the two host plants are specialized on genera in different tribes within the family Asteraceae. In addition, cross-mating experiments showed that gene-flow is only possible in one direction, i.e. when females from Russian knapweed were mated with males from scentless chamomile. However, even then the number of offspring produced was very limited. Because specimens from the two host plants could not be distinguished morphologically, genetic analyses using mtDNA sequencing were conducted, using specimens collected from different geographic regions as well as specimens from related Napomyza species. The results indicate that individuals from scentless chamomile and Russian knapweed should probably be treated as two separate species.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA