Zygogramma suturalis, commonly known as the ragweed leaf beetle, is a species of leaf beetle belonging to the genus Zygogramma.[1] Native to North America, it has been introduced into Russia and China for the biological pest control of ragweed.
This leaf beetle is small with a brown head and pronotum, and yellow elytra marked with two wide margins of brown on each wing; one in the middle and one at the suture.
Z. suturalis is native to Canada and the USA.[1]
It was introduced into Russia in 1978 in an attempt to control invasive Ambrosia artemisiifolia (common ragweed).[2] About 1500 specimens were originally released which had eliminated ragweed at the experimental control site by 1983. The success of Z. suturalis in Russia led to a population explosion with densities of up to 100,000,000 adults per square kilometre recorded subsequently.[3]
It was introduced to China as a biological pest control for ragweed in 1987.[4]
Adults and larvae feed on Ambrosia artemisiifolia (common ragweed), A. psilostachya, and A. trifida.[5]
Overwintering adults began feeding in late April or early May of the following year, having emerged when ragweed seedlings were only 2–5 cm tall.[6] Larvae of the first or spring generation began feeding in mid-May or early June and most reached maturity by early July.[6] Larvae of the second or late summer generation were evident during the first two weeks of August.[6]
No complex courtship behavioural patterns have been observed in Z. suturalis; copulation most commonly takes place during the late morning or early evening and lasts from a few minutes to well over an hour.[6] Females lay between 145 and 563 eggs, over a period of 22–42 days.[6] Eggs are deposited in clusters of two or three on the underside of young ragweed leaves, usually near the leaf tip.[6]
Investigations in the USA showed that Z. suturalis had 2 generations a year,[6] but field investigations in China have shown that the beetle species could have up to 3 generations a year in that populations.[4] At 26±1 °C, the average lifespan of the adult female and male was 82.5 and 67.8 days respectively.[4] The mated females began laying eggs two weeks after emergence. Each female lays an average of 394 eggs.[4]
Wikispecies has information related to Zygogramma suturalis. Zygogramma suturalis, commonly known as the ragweed leaf beetle, is a species of leaf beetle belonging to the genus Zygogramma. Native to North America, it has been introduced into Russia and China for the biological pest control of ragweed.
