Subject: Potato Beetle?
Location: Austin, TX
April 8, 2014 9:46 pm
These bugs have shown up in the last few days. We have had some heavy rains, and today was the first day of sunshine, so this might be why I haven’t noticed them until now. Some are reddish/orange and some are blue. They are the size of ladybugs but do not look like ladybugs. There are at least 300 of these bugs that have attached themselves to the fence in my backyard. We have recently planted our summer garden, full of vegetables and flowers, and I am worried these guys might start to munch, before I have a chance to! Please help!!
Signature: Samantha G
lady beetle (aka Ladybug) larva and pupa
So these are not harmful to the garden, more helpful?
Since you wrote back, we decided to spend a bit more time on both the identification and our response, and to create a posting. With the number of requests we receive, we are only able to post a small fraction of emails and images, but we are able to respond to more with quick replies, like the original and very general answer you got from us. We don’t immediately recognize all species upon viewing images, but we can give general answers that might only reach a broader taxonomic category. Our original answer was to the family level, and we could have also supplied you with a quick second response that yes, your Lady Beetles are not harmful in the garden because they eat Aphids and other small plant pests. Curiosity got the best of us though, and we decided to try to identify your species of Lady Beetle. The larva is that of a Seven Spotted Lady Beetle, Coccinella septempunctata, as evidenced by this image on BugGuide. Sadly, it is not a native species. According to BugGuide: “It has been repeatedly introduced in the US from Europe, to control aphids. This widespread palearctic species was intentionally introduced into N. America several times from 1956 to 1971 for biological control of aphids. All of those attempts apparently failed in getting C. septempunctata established, but in 1973 an established population was found in Bergen Co., New Jersey. This population is thought to have been the result of an accidental introduction rather than a purposeful one (Angalet and Jacques, 1975). Since 1973, this species has spread naturally and been colonized and established in Delaware, Georgia, and Oklahoma. (Gordon 1985) It has since spread throughout N. Amer.” We are not alone in fearing that native Lady Beetles are being rapidly displaced by other more vigorous introduced Lady Beetles, most notably the Multicolored Asian Lady Beetles, Harmonia axyridis, which have become pests in some areas because they enter homes in great numbers to hibernate. They are even known to prey upon native Lady Beetles. Your Seven Spotted Lady Beetle, though introduced, is nowhere near the problem that the Multicolored Asian Lady Beetle represents. Your pupa is also that of a Seven Spotted Lady Beetle as evidenced by this image on BugGuide. In your case, they are more beneficial than a problem in the garden. The concept of introduced species displacing native species is a significant issue as global travel becomes ever easier for people and the critters that travel with them, either purposefully or accidentally.
I appreciate the response!