In my previous post, I discussed how a Densovirus was crippling cricket production all over the country. Acheta domestica Densovirus (AdDNV, for short) is a virus which causes paralysis, and kills almost every cricket it infects. It’s also incredibly resistant to degredation, and appears to spread in dust within facilities, making decontamination nearly impossible. The disease has pushed some cricket breeders into bankruptcy, and the economic fallout has been intense for this industry that relatively few people pay close attention to.
With an intense economic fallout came an equally intense reaction by businesses who want to survive. I started reading about AdDNV to gain insight into the disease. I wanted to know a little bit about the disease, the symptoms, disinfection procedures…stuff which could help me out in my own cricket rearing endeavors. However, I stumbled into a fascinating article published in a 2012 edition of the journal Zootaxa about how the industry has imported many species to solve the problem. Most of these species are potentially invasive, and one species was completely new to science and is unknown outside the pet trade.
First a little bit about cricket biology and why crickets are potentially problematic, environmentally speaking. Acheta domestica, the common house cricket, is the cricket which is most important in the pet trade. It’s been kept as pets since at least the 1700s, and it is only known from captivity (although there appear to be some invasive populations). It is, for all intents and purposes, as domesticated as a dog or cat.
The crickets you hear around your house during the summer are field crickets, genus Gryllus. These crickets are, for the most part, widespread in terms of habitat…and they can be abundant in many areas. Both Gryllus and Acheta have broad diets, and can eat a wide range of plant and animal products in captivity. Both are also hardy, and can withstand a lot of neglect in captivity. Cricket breeders haven’t had luck breeding AdDNV resistant A. domesticus, so replacement seems to be the best strategy to keep producing food for reptiles. Thus, Gryllus species were particularly attractive alternatives to Acheta in culture because they’re hardy and resistant to AdDNV.
The characteristics which make Gryllus species widespread in nature, wide diet preference and tolerance of a broad range of environmental conditions, make them attractive candidates to replace Acheta as pet food. Unfortunately, the fact they’re widespread in nature also means that they’re likely invasive species. Non-native Gryllus species could become invasive if imported into the US, and native Gryllus species could become invasive if imported into a different area of the US.
So, import of exotic Gryllus species isn’t something which should be desirable because of the risk of releasing a potentially invasive species. Unfortunately, this is exactly what happened after the outbreak. As described in the Zootaxa paper, four new species representing two genera were found distributed by American cricket suppliers shortly after the outbreak began. Three were from the genus Gryllus, while another was from genus Gryllodes.
One species, Gryllus bimaculatus, is a European species which is very widespread. It’s range covers at least three continents, from Europe to Asia to Africa. It’s the standard cricket sold in European pet stores, and has replaced A. domestica as a feeder in Europe. Other petstores started selling a native US species, Gryllus assimilis as a feeder species. The USDA has approved G. assimilis because it’s native, whereas sale of the non-native G. bimaculatus is illegal.
A third Gryllus species, also illegal for sale, was found…but this one was unexpected. One particular type of cricket, the Crazy Red cricket, assumed to be G. assimilis, was found to be quite distinct from any of these. Although it looked similar to G. assimilis, it’s song was different than any other Gryllus species. The Crazy Red was eventually discovered genetically distinct from native crickets. In fact, they were a species which had not been described before. That is, they were completely new to science and nothing was known about their biology-except, of course, that they were resistant to AdDNV. They appear to be related to New World crickets, those from North and South America, but all anyone knows about them is that they might be American. The species was named Gryllus locorojo after it’s common name-locorojo is ‘crazy red’ in Spanish.
I’m not privvy to a lot of details about how the cricket industry is regulated, but I suspect that this potentially serious issue won’t be resolved anytime soon. Crickets, due to their generalist and resilient nature, are potential invasives. Crickets can get released in lots of ways, which makes them especially risky. Pet owners release them into the wild on purpose, some escape during transfer…it’s just very likely these crickets will end up in the environment one way or another.
Even worse, it appears the USDA has little power to regulate the market. Regulations in California are a lot more lax than the federal regulations. Even if this weren’t the case, the USDA appears to have little power to regulate the market because the agency lacks a cricket taxonomist.
The industry, for their credit, has apparently adopted the less invasive species. Gryllus locorojo had a reputation for being aggressive, whereas the others were a bit more docile. Many cricket farms nowadays advertise their stock as Acheta domesticus, although there’s no way to know what you’d get unless you ordered some. Many don’t have the identification advertised.
There was a fourth species which was imported, Gryllodes sigillatus. This species is found largely in tropical climates, but it’s always found around people. It appears to have adapted to human habitations, and lives specifically in the types of environment we create. According to researchers, it’s the best choice for Acheta replacement as it’s resistant to AdDNV and has a narrow habitat tolerance…which means it’s unlikely to be invasive. The USDA also seems to have been issuing permits for the sale and transport of this species.
I wasn’t aware of any of these issues when I started shopping for my own crickets, and I’m glad I found out about this stuff. I got curious, and decided to look at my breeding stock a bit closer. The females were brown, with wings extended past the tip of the abdomen like the picture above from Weissman et. al 2012 (cited below)…which means I procured A. domesticus.
So even after all this, the original A. domesticus are still for sale.
Weissman D., Gray D., Pham H. & Tijssen P. (2012). Billions and billions sold: Pet-feeder crickets (Orthoptera: Gryllidae),
commercial cricket farms, an epizootic densovirus,
and government regulations make for a potential disaster, Zootaxa, 3504 67-88. DOI: