Genus Scapteriscus
two-clawed mole crickets

Key to genera of mole crickets (Gryllotalpidae).
Members of this genus have two blade-like claws (dactyls) on each foretibia and the auditory tympanum is exposed. The foretrochanter is armed with an elongate blade. The hindtibia has 3-6 long spines along its upper inner margin.

Our three species in this genus are native to South America and first became established in North America more than 90 years ago, apparently from stowaways in ships' ballast. Maps of when and where they were introduced and how they spread are on the species pages and in Walker & Nickle (1981).
 
Scapteriscus spp. and Neocurtilla
foretibiae
trochantal blades
seasonal life cycles
flight seasons
calling and flying
 
 
diets
 
 

Life cycles

Two-clawed mole crickets require a year or less for a generation. In the colder parts of their ranges they overwinter both as adults and large nymphs. Eggs are laid in clutches of 25 to 60 in small ovoid chambers (4 x 3 cm) 9 to 30 cm below the surface.

Economic importance

Members of this genus are the most damaging crickets in the New World. In the southeastern United States tawny mole crickets (S. vicinus) are major pests of established lawns and pastures, causing annual losses of $10's of millions. Short-winged mole crickets (S. abbreviatus) do the same type of damage but are much more restricted geographically. Southern mole crickets (S. borellii) feed largely on animal matter and avoid established turf; however, they damage seedlings in newly planted lawns, gardens, and fields.

Biological control

Because our pest mole crickets were introduced and occurred in much greater numbers here than in their homeland, University of Florida researchers concluded that they might be controlled by classical biological control--that is, by introducing natural enemies that had been left behind when they immigrated from South America. Of the enemies that proved promising because of their host specificity, three have been successfully introduced, and have substantially reduced Scapteriscus populations. Steinernema scapterisci is a nematode that kills mole crickets by introducing lethal microbes (Parkman et al 1993). Ormia depleta is a tachinid fly that homes on the calling songs of male mole crickets and deposits living larvae that enter and consume mole crickets (Frank et al 1996). Larra bicolor is a sphecid wasp that chases a mole cricket from its burrow, subdues it with a sting and glues an egg at the base of a middle leg. The mole cricket recovers but the egg becomes a larva that feeds on the cricket while attached externally and eventually kills its host and consumes the remains (Walker 1984).

Flights

Large numbers of tawny and southern mole crickets fly during the early evening of warm days each spring. One result of such flights is that new lawns and fields are infested and pesticide-treated ones are re-infested. Another result is that females find mates by homing to the appropriate calling song and landing near the entrance to the caller's burrow.

Some important features of the flights are not adequately understood. Males and mated females, as well as virgin females, often terminate their flights by homing to conspecific calling song, and the same individual may fly and home repeatedly over a period of several weeks. Available evidence suggests that many flights terminate near their starting points and that in heavily infested fields a minority of the males call each evening. Pair formation and sexual competition in these species deserve further study. Most flights probably involve more than colonizing new or better fields or finding a willing source of conspecific sperm. T.G. Forrest (1983) has shown that calling males vary greatly in their attractiveness to females. On an evening when one calling male attracts no female, another, calling nearby, may attract more than 20! (He cannot service so many--Forrest prevented them from reaching the male.) Male attractiveness correlates with loudness of the calling song. Loudness correlates with both male size and soil moisture, which in turn are indicative of male quality and habitat quality. Scientists have exploited the attractiveness of loud calls by broadcasting simulated mole cricket sounds more than 30 times as powerful as the loudest male and have collected as many as 8000 mole crickets at a single sound source in a single evening.

References

Bennet Clark HC. 1987. The tuned singing burrow of mole crickets. J. Exp. Biol. 128: 383-410. [S. borellii]

Brandenburg RL, Xia Y, Schoeman AS. 2002. Tunnel architectures of three species of mole crickets (Orthoptera: Gryllotalpidae). Fla. Entomol. 85: 383-385. [2425 KB]

Forrest TG. 1980. Phonotaxis in mole crickets: its reproductive signifiance. Fla. Entomol. 63: 45-53. [700 KB]

Forrest TG. 1983. Calling songs and mate choice in mole crickets. In: Gwynne DT, Morris GK, editors. Orthopteran mating systems: sexual competition in a diverse group of insects. Boulder CO: Westview. p 185-204. [1442 KB]

Forrest TG. 1986. Oviposition and maternal investment in mole crickets (Orthoptera: Gryllotalpidae): Effects of season, size, and senescence. Ann. Entomol. Soc. Am. 79: 918-924. [Scapteriscus borelli and S. vicinus]

Forrest TG. 1987a. Insect size tactics and developmental strategies. Oecologia 73:178-84. [Scapteriscus borellii and S. vicinus]

Forrest TG. 1987b. Sinistrality in the southern and tawny mole crickets, Gryllotalpidae: Scapteriscus. Fla. Entomol. 70: 284-286. [258 KB]

Forrest TG, Green DM. 1991. Sexual selection and female choice in mole crickets (Scapteriscus: Gryllotalpidae): Modelling the effects of intensity and male spacing. Bioacoustics 3:93-110.

Fowler HG, Justi JJ, Costa MML. 1986. Subterranean cage studies on field survivorship of Scapteriscus borellii (Orthoptera, Gryllotalpidae). Naturalia 12: 43-46.

Fowler HG, Garcia CR. 1987. Attraction to synthesized songs and experimental and natural parasitism of Scapteriscus mole crickets (Orthoptera: Gryllotalpidae) by Euphasiopteryx depleta (Diptera: Tachinidae). Rev. Bras. Biol. 47: 371-374.

Fowler HG. 1987. Spatial distribution and behavior of calling Scapteriscus vicinus (Orthoptera: Gryllotalpidae) in Brazil. Rev. Bras. Biol. 47: 297-300.

Frank JH, Walker TJ, Parkman JP. 1996. The introduction, establishment, and spread of Ormia depleta in Florida. Biol. Control 6: 368-377. [parasitoid of Scapteriscus spp.] [3698 KB]

Hebard M. 1909. A species of molecricket new to the United States. Entomol. News 20: 179. [Scapteriscus vicinus]

Henne DC, Johnson SJ. 2001. Seasonal distribution and parasitism of Scapteriscus spp. (Orthoptera : Gryllotalpidae) in southeastern Louisiana. Fla. Entomol. 84: 209-214. [Scapteriscus vicinus and S. borellii]

Hudson WG. 1987. Variability in development of Scapteriscus acletus (Orthoptera: Gryllotalpidae). Fla. Entomol. 70: 403-404. [S. borellii]

Kleyla PC, Dodson G. 1978. Calling behavior and spatial distribution of two species of mole crickets in the field. Ann Entomol Soc Am 71: 602-604. [Scapteriscus vicinus and S. borellii]

Mason AC, Forrest TG, Hoy RR. 1998. Hearing in mole crickets (Orthoptera: Gryllotalpidae) at sonic and ultrasonic frequencies. J. Exp. Biol. 201: 1967-1979. [Scapteriscus borellii and S. abbreviatus]

Matheny EL, Jr. 1981. Contrasting feeding habits of pest mole cricket species. J. Econ. Entomol. 74: 444-445.

Matheny EL, Jr., Kepner RL, Portier KM. 1983. Landing distribution and density of two sound-attracted mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus). Ann. Entomol. Soc. Am. 76: 278-281. [454 KB]

More JD. 1924. The mole cricket (Scapteriscus vicinus Latr). Ga. Exp. Sta. Bull. 101: 3-12.

Ngo D, Beck HW. 1982. Mark-release of sound-attracted mole crickets: flight behavior and implications for control. Fla. Entomol. 65: 531-538. [520 KB]

Nickerson JC, Snyder DE, Oliver CC. 1979. Acoustical burrows constructed by mole crickets. Ann. Entomol. Soc. Am. 72: 438-440.

Nickle DA. 1992. Scapteriscus borellii Giglio-Tos: the correct species name for the southern mole cricket in southeastern United States, Orthoptera: Gryllotalpidae. Proc. Entomol. Soc. Wash. 94: 524-526. [Scapteriscus borellii] [261 KB]

Parkman JP, Hudson WG, Frank JH, Nguyen KB, Smart, GC Jr. 1993. Establishment and persistence of Steinernema scapterisci, Rhabditida: Steinernematidae, in field populations of Scapteriscus spp. mole crickets, Orthoptera: Gryllotalpidae. J. Entomol. Sci. 28: 182-190.

Ulagaraj SM. 1975a. Mole crickets: ecology, behavior, and dispersal flight (Orthoptera: Gryllotalpidae: Scapteriscus). Environ. Entomo.l 4: 265-273. [1079 KB]

Ulagaraj SM. 1975b. Food habits of mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus). J. Georg. Entomol. Soc. 10: 229-231.

Ulagaraj SM. 1976. Sound production in mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus). Ann. Entomol. Soc. Am. 69: 299-306. [1097 KB]

Ulagaraj SM, Walker TJ. 1973. Phonotaxis of crickets in flight: attraction of male and female crickets to male calling songs. Science 182: 1278-1279.  [416 KB]

Ulagaraj SM, Walker TJ. 1975. Response of flying mole crickets to three parameters of synthetic songs broadcast outdoors. Nature 253: 530-532.  [223 KB]

Walker TJ. 1982. Sound traps for sampling mole cricket flights (Orthoptera: Gryllotalpidae: Scapteriscus). Fla. Entomol. 65: 105-110.  [Scapteriscus borellii and S. vicinus] [579 KB]

Walker TJ, editor. 1984. Mole crickets in Florida; Univ. Fla. Agric. Exp. Sta. Bull. 846. 54 p.

Walker TJ. 1984. Biology of pest mole crickets: systematics and life cycles. Univ. Fla. Agric. Exp. Sta. Bull. 846: 3-10.

Walker TJ, Forrest TG. 1989. Mole cricket phonotaxis: Effects of intensity of synthetic calling song (Orthoptera: Gryllotalpidae: Scapteriscus acletus).  Fla. Entomol. 72: 655-659.  [380 KB]

Walker TJ, Fritz GN. 1983. Migratory and local flights in mole crickets (Scapteriscus acletus and S. vicinus). Environ. Entomol. 12: 953-958. [Scapteriscus borellii and S. vicinus]  [5543 KB]

Walker TJ, Littell RC, Dong N. 1982. Which mole crickets damage Bahiagrass (Paspalum notatum) pastures? Fla. Entomol. 65: 110-116. [Scapteriscus borellii and S. vicinus]

Walker TJ, Nation JL. 1982. Sperm storage in mole crickets: fall matings fertilize spring eggs in Scapteriscus acletus. Fla. Entomol. 65: 283-285.  [260 KB]

Walker TJ, Ngo D. 1982. Mole Crickets and pasture grasses: damage by Scapteriscus vicinus, but not by S. acletus. Fla. Entomol. 65: 300-306. [540 KB]

Walker TJ, Nickle DA. 1981. Introduction and spread of pest mole crickets: Scapteriscus vicinus and S. acletus reexamined. Ann. Entomol. Soc. Am.74: 158-163.  [+ S. abbreviatus] [1152 KB]

Walker TJ, Reinert JR, Schuster DJ. 1983. Geographical variation in flights of mole crickets, Scapteriscus spp. (Orthoptera: Gryllotalpidae).  Ann. Entomol. Soc. Am. 76: 507-517. [Scapteriscus borellii and S. vicinus]  [1417 KB]