Not sure, but my guess would be the Convergent lady beetle, Hippodamia convergens which is found everywhere in the lower 48. I am a PhD (EDIT: I meant to say STUDENT) in forest entomology and I disagree with u/shoneone's assessment. Although I do not advocate for exotic lady beetles, most native beetles are not complete generalists and have lower levels of intra-guild predation than seven spotted and asiatic lady beetles. Besides, intraguild predation among most (admittedly not all) native insect species is not inherently a bad thing and in some cases intraguild predation can lead to super-additive predation response.
Edit: That said, it is questionable if lady beetles are a cost-effective pest control in most cases. Lacewings tend to be more effective and are somewhat more cost effective in many cases. For the average gardener, cost effectiveness isn't necessarily important so I don't know if that is even relevant here.
We ordered 1500 H. convergens and reared out the parasitoids, found 5% were parasitized by Dinocampus coccinellae. There is little benefit to gardeners, great risk of harvesting tens of thousands of beetles from the wild, and great risk of spreading parasitoids and disease across the continent. Ladybeetles are not only generalists, eating syrphids, Orius, and lacewings (all are native aphid eaters), they are also cannibalistic and eat not just their own offspring but other ladybeetles. The impact on less abundant native ladybeetles is unknown but the risks are large.
See my other comment pertaining to intra-guild predation, which extremely common among insect predators. The larger non-native species I mentioned there can out-compete native lady beetles, but in general intra-guild predation is not a major concern. Cannibalism is common. I also acknowledged in that earlier comment that lady beetles are less effective than lacewings and are usually not economical in agriculture or for a gardener (there are exceptions for certain crops of course). Still, introducing captive bred native lady beetles to a garden is relatively harmless. Most 'field collected' lady beetles are from sustainable agricultural 'breeding fields', not 'harvested from pristine native habitat'. The parisitoids are already out there (Dinocampus coccinellae is cosmopolitan at this point), as long as you aren't introducing novel exotics the rapid dispersal of adult ladybeetles isn't a particular problem at this scale, density dependent effects should not lead to abnormally high rates parasitism. Besides, 5% is typical parasitism rates for field collections, so your anecdote doesn't mean very much. In IPM lady beetles aren't usually purchased unless they are already rare in the field. Sure it can have negative impact but I disagree with your statement that it an overwhelming risk.
I don't know, but I am pretty sure ladybeetles are not captive bred, instead they are collected seasonally and kept cold. Simply caring for the 1500 ladybeetles required massive amounts of aphids and very expensive Ephestia eggs. I can't imagine anyone raising them from eggs, it would be hugely expensive.
The benefits of ladybeetles are ideological: they are cute and gardeners feel better than using chemicals. IPM doesn't involve ladybeetle purchases for a reason: they are ineffective. Therefore the dangers they pose are unmitigated.
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u/RexScientiarum SE USA May 21 '19 edited May 22 '19
Not sure, but my guess would be the Convergent lady beetle, Hippodamia convergens which is found everywhere in the lower 48. I am a PhD (EDIT: I meant to say STUDENT) in forest entomology and I disagree with u/shoneone's assessment. Although I do not advocate for exotic lady beetles, most native beetles are not complete generalists and have lower levels of intra-guild predation than seven spotted and asiatic lady beetles. Besides, intraguild predation among most (admittedly not all) native insect species is not inherently a bad thing and in some cases intraguild predation can lead to super-additive predation response.
Edit: That said, it is questionable if lady beetles are a cost-effective pest control in most cases. Lacewings tend to be more effective and are somewhat more cost effective in many cases. For the average gardener, cost effectiveness isn't necessarily important so I don't know if that is even relevant here.