Chilly temperatures and wintry weather create conditions unfavorable for hunting and photographing bugs in the wilds of Maryland. This week we returned to our mailbox to answer questions sent by bug aficionados earlier in the year. This week’s “What is it?” came from Talbot County, Maryland where an observant gardener discovered an insect’s egg case attached to a shrub in her yard. The egg case in question was about an inch long with the look and feel of an elongated glob of Styrofoam.
Tiny mantids emerge from their egg case and hunt small insects in spring.
The entomological term for the egg case is an ootheca. A mantid’s ootheca is composed of frothy material called spumalin that serves as a protective matrix for dozens of tiny mantid eggs within. The mamma mantid secretes spumaline from glands in her abdomen as she deposits eggs usually on vegetation or on structures such as fences and houses. This particular ootheca was deposited by a Carolina mantid in late autumn last year. After surviving the chill of winter, eggs complete their development with the return of warm weather. Warm weather signals the return of foliage to plants and the presence of legions of small tasty insects that serve as food for developing mantids. We visited other species on mantids in previous episodes on Bug of the Week such as Chinese and European mantids. Unlike these foreigners, the Carolina mantid is native to North America. It ranges from New Jersey, south to Florida and west to Arizona.
A gorgeous Carolina mantid waits for a meal or perhaps a mate who might be a dinner guest.
Like other mantid species, Carolina mantids eat a wide variety of insects and spiders found in gardens and landscapes. And yes, on occasion the female consumes her unfortunate mate especially when mantids are raised in captivity. The extent to which this is an artifact of being raised under unusual conditions is not known, but it is reported that well fed gals are less likely to consume their suitors than hungry ones. With Valentine’s Day just around the corner, perhaps there is a lesson here. Although egg cases of praying mantids can be purchased commercially and placed in the garden, the effectiveness of mantids as biological control agents is ambiguous at best. They are generalist predators and may capture and eat beneficial insects as well as pests. Nonetheless, mantids are fascinating to observe and study and I always have an ootheca or two in my landscape to restock my garden when spring returns.
References:
Bug of the Week thanks Suzanne for sending images and providing the inspiration for this Bug of the Week. To learn more about the Carolina mantid, please visit the following web site.
http://animaldiversity.ummz.umich.edu/site/accounts/information/Stagmomantis_carolina.html