The male’s stridulatory apparatus is almost perfectly symmetrical, that is, males have fully functional files and scrapers on both tegmina and can produce sound with either the left or r
Trang 1Hagloidea (Grigs or Hump-Winged Crickets)
This ancient superfamily, dating back to the early Jurassic
period, is represented by only eight extant species placed in a
single family Prophalangopsidae (Figure 2) They are
charac-terized by a rather primitive stridulatory apparatus lacking a
proper mirror, head with antennae inserted near the lower
margin of the eyes, and the metatarsus with a well-developed
pulvillus The largest of these Mesozoic relics is Prophalangopsis
obscura, with the wingspan of more than 100 mm, found on
the Tibetan Plateau The remaining eight species belong to
four genera distributed in western North America
(Cypho-derris ) and northeastern Asia (Paracyphoderris, Aboilomimus,
and Tarragoilus) The biology of Cyphoderris is quite well
known and some species of the genus are often used in studies
on mating behavior and parental investment in offspring The
male’s stridulatory apparatus is almost perfectly symmetrical,
that is, males have fully functional files and scrapers on both
tegmina and can produce sound with either the left or right
tegmen (hence the name ‘‘ambidextrous crickets,’’ is
some-times applied to these insects) The hindwings are reduced to
fleshy lobes, which are devoured by the female during
copu-lation Males who had already mated once and are missing
these courtship ‘‘snacks’’ must resort to other methods of
holding the female’s attention and instead use the ‘‘gin trap,’’ a
complex system of cuticular modifications whose role is to
hold the female’s abdomen firmly in place during copulation
These insects are also unique in their ability for being active,
and even call during winter, from snow-covered bushes, when
the temperature oscillates at approximately 0 1C
Grylloidea (Crickets and Mole Crickets)
Introduction
The superfamily Grylloidea includes nearly 5300 described
species placed in more than 670 genera and four families
(Figure 3) Crickets are small- to medium-sized insects, the
smallest species being only approximately 1.5 mm long
(Myrmecophilidae) and the largest approximately 60 mm
(Gryllotalpidae) The family is cosmopolitan in its
distri-bution and some species occur even within the polar regions,
albeit usually only in association with human dwellings Most members of the subfamily are brown or black, very rarely green The antennae are usually thin, threadlike, and longer than the body (with the exception of certain burrowing forms) The head is usually large and almost globular, al-though it may be somewhat elongate and prognathous in some lineages (Oecanthinae and Gryllotalpidae) The prono-tum is usually quadrate, rarely produced backward as to cover the wings (a condition common in katydids) The tarsi of the legs are three segmented (superficially four segmented in Oecanthinae), and the front legs are sometimes strongly modified for digging The front tibia typically have well-developed bilateral tympanal organs Hind legs are usually saltatorial but are occasionally short and not adapted for leaping Wings are usually present but may be reduced to various degrees or totally absent (Myrmecophilidae) The tegmina are held flat on the dorsum and their anterior (lateral,
in the resting position) margins are bent downward at an angle, forming a box-like structure The stridulatory apparatus
of males is well developed in most groups, although it may be absent even in some fully winged taxa (some Pentacentrinae, Trigonidiinae, and Eneopterinae) The left and right tegmina
of males have similar venation, but stridulation is performed virtually always with the right tegmen rather than with the left tegmen The hindwings, when folded, often project far beyond the tegmina Many taxa lack the hindwings and wing poly-morphism is common Male cerci are usually long, flexible, often superficially annulated, and never grasping The ovi-positor is usually long and needlelike, although it may be reduced or even absent in some crickets (Gryllotalpidae) Most species of crickets are nocturnal or crepuscular They occur in almost all terrestrial habitats, from treetops to underground burrows, and many species are associated with aquatic and semiaquatic environments (such forms are usually very good swimmers) The great majority of crickets are opportunistic feeders and few seem to be exclusively predaceous
Major Lineages
Gryllotalpidae (Mole Crickets)
This interesting family, which includes six genera and more than 100 described species of usually large, robust crickets, are
Figure 2 Hagloidea: Grig Cyphoderris strepitans from
Wyoming, USA
Figure 3 Grylloidea: Field cricket Gryllus veletis from
northeastern USA
728 Grasshoppers and their Relatives