House cricket and tropical house cricket differences
Crickets are wonderful creatures that remind us of beautiful meadows at night. Hearing them chirping is a great experience outdoors. However, things become very different when they move inside. Nobody likes to hear crickets chirping non-stop in the kitchen for hours. There are different types of crickets. Field crickets in the genus Gryllus, are those normally leaving outdoors and rarely get close to buildings. In the U.S., they are usually blackish in color and rarely seen indoors. However, there are other crickets such as the house cricket (Acheta domesticus) and the tropical house cricket (Gryllodes sigillatus) which primarily live around human dwellings. These are the ones that become structural pests and can be very annoying. Male crickets seek shelters to chirp and find mates. In this process, they may enter homes through various entry points and eventually hide under furniture, kitchen appliances, and other types of hiding places.
Many people including the pest control industry may not be aware that there are two different species of crickets infesting urban areas in California. Here, I will describe each and point out some morphological and behavioral differences.
Differences of the house cricket and tropical house cricket
These two look somewhat similar but can be distinguished by several features mentioned below
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General Appearance: Both species have an appearance ranging from light tan to dark brown, or even black. However, tropical house crickets tend to be lighter in color.
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Bands on the head: Both have 2 or more transverse bands on their head. In house crickets, the bands are dark and sometimes wider. In tropical house crickets, the bands are a bit less pronounced and the band on the back of the head is missing or incomplete. Instead of a whole dark band, there are dark veins on the back (posterior) parts of the head of tropical house crickets.
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Space between antennae: The first segment of antenna is called the "scape". In house crickets, the space between scapes of antennae is wider than in tropical house crickets. In tropical house crickets, the scape is larger, taking more space on the forehead and therefore narrowing the space between the base of antennae.
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Wings: Both male and female house crickets have longer wings, covering most of their abdomen. In contrast, male tropical house crickets have shorter wings covering only half of their abdomen and females only have wing pads and are almost wingless.
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Courtship behavior: Male tropical house crickets are known to provide a nuptial gift to females during courtship. House crickets are not known for such behavior. A nuptial gift is a nutritious material produced by males to encourage courtship in insects, but may have other roles too. In tropical house crickets, males and females are ready to mate in 3 and 1.5 days after becoming adults, respectively. Male crickets attract females by rubbing their front wings together to produce chirping sound. Females are attracted to the chirping sound and when they get close enough, males use their antenna to identify females. Prior to mating, the male releases a soft transparent and gelatinous material called the, the mating jelly. During mating, the female moves over the male and the spermatophore and mating jelly are transferred into the genital of females. Mating doesn't last long and takes 3-4 minutes on average. Very soon after mating, the female removes the mating jelly and starts feeding on it. The spermatophore which contains the sperms, stays inside the genitalia for about half an hour, after which it is removed by the female. By that time the spermatophore is empty. The exact role of spermatophore is not well understood. Although it is not absolutely necessary during mating, the mating jelly may increase the chance of successful spermatophore transfer during mating (Subramaniam and Subramoniam 1990).
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Climate: Tropical house crickets are more common in hotter climates and house crickets may be found in relatively cooler climates. They co-exist in many areas of the southern U.S. as well as in Mexico.
Management
Crickets can be effectively controlled using granular baits. Sprinkling attractive granular baits outdoors can quickly eliminate or significantly reduce cricket populations. However, not all baits are equally attractive to crickets. I have had great success with Advion Insect Granule (EPA Registration number: 100-1483). These baits are very attractive to tropical house crickets of Southern California and you can see them munching on them right after application. There are several other granular bait products on the market, but I either didn't have good results with them or haven’t tested them yet. While some granular baits can be very effective in controlling tropical house crickets, it is important to know that relying on insecticidal bait alone is not a sustainable way of managing them. Crickets constantly cross property lines and aggregate under stones, debris, and concrete (driveway or sidewalks). As a result, it is important to remove their harborage or hiding places to reduce their reproduction rate.
References
- Subramaniam M, Subramoniam T. 1990. Mating Behaviour and Spermatophore Transfer in Gryllodes sigillatus (Walker) (Orthoptera: Gryllidae). Zoosystematics & Evolution. 66(1):65–71. https://doi.org/10.1002/mmnz.19900660108