| C. miniatus female from
Tijuana Estuary (photo by Chris Brown) |
Background
Yet another fascinating and poorly
understood insect resides in Southern California: the silk spinning
cricket (Cnemotettix miniatus). These insects are the only
Orthoptera known to spin silk (produced from their maxillary glands). This
silk is used to to reinforce their burrows in sandy areas. There are five described silk-spinning crickets known in Califorina (Cnemotettix spinulus, C. caudulus , , C. pulvilliferC. bifasciatus, and C. miniatus). The first three species are restricted to the Channel Islands, while C. bifasciatus is distributed along the central coastal range and through the mountains of Southern California. Until recently, C. miniatus was thought to occur only on the Santa Catalina Island, and in the Tijuana Estuary. But, intensive sampling of Southern California coastal habitats (as part of a long-term monitoring project currently conducted by the San Diego Field Station) has uncovered several populations residing in patches of coastal sage scrub and maritime scrub habitats in San Diego and Orange County.
Most of the natural coastal habitats in Southern California have been lost to development, and the little that remains is highly fragmented. Within these fragments, C. miniatus appears to be very rare, suggesting that populations may be threatened due to reduced habitat and reduced habitat connectivity. Again, we are using a molecular approach to assess the status of silk-spinning cricket populations throughout Southern California. With this study, we hope to answer the following questions:
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- What is the distribution of genetic diversity within and among remnant populations?
- Have populations undergone recent genetic bottlenecks due to loss of habitat ?
- Do remaining populations require special conservation protection?
