26 August 2013

Mole Cricket - Gryllotalpa sp.

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Mole Cricket - Gryllotalpa sp. 

Mole Crickets live in underground burrows, where the male will call the female by positioning himself at the entrance and instead of singing to the outside, will turn around and sing back into his burrow; this unusual procedure not only amplifies his call, but also lets the female know if the burrow is moist or dry. This is important as females prefer a moist burrow to lay her eggs and a male with such endowed real estate will more readily attract a mate. 

There are eleven Australian Mole Crickets, which range over much of the country, but due to the female’s preference for moisture, they generally are more common in well-watered areas, especially irrigated lawns. The female will remain with the eggs until they hatch and even show maternal care by protecting the young nymphs. 

The heath around Esperance is predominantly a dry habitat, but there are many swampy areas that slowly drain from one area to another, which I presume is what attracts these insects, although I seldom encounter them. The photographed male above has undeveloped wings and never flies, whereas the female has fully developed wings and can move around freely, being guided by the loud calls of the male, which she does on warm summer evenings after or with the promise of rain. 

The strong fore-legs are specifically adapted for digging and used to reach the roots of plants on which it feeds, therefore Mole Crickets have little reason to leave their burrows other than for mating or escaping predators like spiders and large centipedes. However there is another and more dangerous predator, that being a large wingless metallic blue wasp commonly called a ‘Blue Ant’ which after paralysing the cricket with her stinger, will deposit an egg whose larvae will consume it after hatching. The female Blue Ant is around 2.5 cm (1’) in length and just a little shorter than the Mole Cricket, which is closer to 3 cm. 

Gryllotalpa is the only genus of the Gryllotalpidae family.