Gryllus rubens

Gryllus rubens, commonly known as the southeastern field cricket, is one of many cricket species known as a field cricket.[1][2] It occurs throughout most of the Southeastern United States. Its northern range spans from southern Delaware to the extreme southeastern corner of Kansas, with a southern range stretching from Florida to eastern Texas.[3]

Gryllus rubens
Gryllus rubens in Alabama
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Orthoptera
Suborder: Ensifera
Family: Gryllidae
Genus: Gryllus
Species:
G. rubens
Binomial name
Gryllus rubens
(Scudder, 1902)

Description

Morphology

Gryllus rubens has been found to be morphologically indistinguishable from G. texensis, with which it shares its range. Compared to G. texensis, female G. rubens are found to have longer ovipositors.[4] It has been found that G. rubens has a peripatric origin derived from one lineage of geographically subdivided ancestor of G. texensis.[5]

Wing morphology

Many studies on G. rubens revolve around their ability to exhibit wing polymorphism. Many of which are done in northern Florida where G. rubens occurs year-round. In the spring/summer seasons, G. rubens is often found to have long wings that reach the end of their abdomen.[6] While in the autumn/winter seasons G. rubens tend to be short winged. These results showed that the environment plays big role in determining wing morph in G. rubens. However, a later study identified that in female G. rubens, genotype plays a bigger role in determining wing morph and in males the environment plays a bigger role in determining wing morph.[7] Thus it was concluded that genes for wing morph is strongly influenced by the environment. A few years later, a study found that short winged female G. rubens oviposit earlier and with more eggs than their long winged counterparts.[8] It is suggested that due to the longer wings, more nutrients are being allocated to maintain the wings. Which causes long wing morphs to have smaller ovaries and produce fewer eggs. Alternatively, short winged male G. rubens have not been found to reach sexual maturity earlier nor have a difference in reproductive output compared to long winged males.[9]

Digestion

Gryllus rubens have three major digestive enzymes: protease, amylase and lipase in their midgut and hindgut. Previously, it was believed that only midgut had the biggest contribution to breaking down food but it was discovered that the hindgut contributes just much enzymatic activity as the midgut to break down food to nutrients.[10]

Courtship songs

One of the main difference between the cryptic sister species G. rubens and G. texensisis the structure of their call courtship song.[11] Specifically, G. rubens have more low-frequency ticks per phrase and more pulses per trill in their courtship songs.[12]

A study in 2006 investigated female G. rubens response to conspecific courtship songs from males dependent on season. The results showed that fewer females would approach the broadcaster during the autumn, and females would spend less time near the broadcasting male during the fall.[13]

Another study in 2011 investigated male G. rubens responses upon hearing another male make conspecific advertisement signals. It was found that younger G. rubens responded phono-tactically, while older crickets will respond acoustically.[14] In simple terms, upon hearing the conspecific song, young crickets will move towards and approach the courtship song, possibly in attempts to steal wondering females; while older G. rubens will respond with a song of their own.

G. rubens also has occurred alongside G. firmus in portions of its range and can be difficult to differentiate. They can be distinguished by their call song and forewing color pattern. G. rubens has a slower call song than G. firmus. Its forewings also have a pale lateral field with inconspicuous veins and crossveins. G. firmus has venation that is paler than the background of the lateral field.[15]

Predators

The tachinid fly Ormia ochracea is a parasitoid of several crickets including G. rubens.[16] This fly uses the courtship songs of G. rubens in order to locate potential hosts, as O. ochracea have been shown to be attracted to the songs of crickets.[17] After locating the host cricket, O. ochracea females deposit larvae, which then quickly burrow into the host. The larvae develop within the host before emerging in about 7 days, killing the host.[18]

References
  1. "Gryllus rubens Scudder, 1902". Integrated Taxonomic Information System.
  2. "Gryllus rubens (Southeastern Field Cricket)". Zipcode Zoo. Retrieved August 3, 2011.
  3. "Gryllus rubens (Southeastern Field Cricket)". University of Florida Entomology and Nematology Department. Retrieved August 3, 2011.
  4. Gray, D.A.; Walker, T.J.; Conley, B.E.; & Cade, W.H. (2001). "A morphological means of distinguishing females of the cryptic species. Gryllus Rubens and G-texensis (orthoptera, gryllidae)". Florida Entomologist. 84 (2): 314–315. doi:10.2307/3496190. JSTOR 3496190.
  5. Gray, D.A.; Huang, H.T.; Knowles, L.L. (2008). "Molecular evidence of a peripatric origin for two sympatric species of field crickets (Gryllus rubensand Gryllus texensis) revealed from coalescent simulations and population genetics" (PDF). Molecular Ecology. 17 (17): 3836–3855. doi:10.1111/j.1365-294x.2008.03827.x. hdl:2027.42/74448.
  6. Walker, T.J. (1987). "Wing dimorphism in Gyllus rubens(Orthoptera: Gryllidae)". Annals of the Entomological Society of America. 80 (5): 547–560. doi:10.1093/aesa/80.5.547.
  7. Zera, A.J.; Rankin, M.A. (1989). "Wing dimorphism in Gryllus rubens: genetic basis of morph determination and fertility differences between morphs". Oecologia. 80 (2): 249–255. Bibcode:1989Oecol..80..249Z. doi:10.1007/bf00380159. PMID 28313115.
  8. Mole, S.; Brockman, A.J. (1993). "Differential allocation of resources underlies the dispersal reproduction trade-off in wing dimorphic cricket, Gryllus rubens". Oecologia. 93 (1): 121–127. Bibcode:1993Oecol..93..121M. doi:10.1007/bf00321201.
  9. Holtmeier, C.L.; Zera, A.J. (1993). "Differential mating success of male wing morphs of the cricket, Gryllus rubens". The American Midland Naturalist. 129 (2): 223–233. doi:10.2307/2426502. JSTOR 2426502.
  10. Thomas, K.K.; Nation, J.L. (1984). "Protease, amylase, and lipase activity in the midgut and hindgut of the cricket Gryllus rubens and mole cricket Scapteriscus acletus". Comparative Biochemistry and Physiology Part A: Physiology. 79 (2): 297–304. doi:10.1016/0300-9629(84)90432-8.
  11. Cade, W.; Otte, D. (2000). "Gryllus texensis n. sp.: A Widely Studied Field Cricket (Orthoptera; Gryllidae) from the Southern United States". Transactions of the American Entomological Society. The American Entomological Society. 126 (Part 1): 117–123.
  12. Fitzpatrick, M.J.; Gray, D.A. (2001). "Divergence between the courtship songs of the field crickets Gryllus texensis and Gryllus ruben(orthoptera, gyllidae)". Ethology. 107 (12): 1075–1085. doi:10.1046/j.1439-0310.2001.00730.x.
  13. Vélez, M.J.; Brockmann, H.J. (2006). "Seasonal variation in female response to male calling song in the field cricket, Gryllus rubens". Ethology. 112 (11): 1041–1049. doi:10.1111/j.1439-0310.2006.01262.x.
  14. Jang, Y. (2011). "Male responses conspecific advertisement signals in field crickets Gryllus rubens (orthopteran: gryllidae)". PLOS ONE. 6 (1): e16063. doi:10.1371/journal.pone.0016063. PMC 3024404. PMID 21283758.
  15. "Drawings are of the right forewings of male Florida field crickets". University of Florida Entomology and Nematology Department. Retrieved August 3, 2011.
  16. Lehmann, Gerlind U.C. (January 2003). "Review of Biogeography, Host Range and Evolution of Acoustic Hunting in Ormiini (Insecta, Diptera, Tachinidae), Parasitoids of Night-calling Bushcrickets and Crickets (Insecta, Orthoptera, Ensifera)". Zoologischer Anzeiger - A Journal of Comparative Zoology. 242 (2): 107–120. doi:10.1078/0044-5231-00091. ISSN 0044-5231.
  17. Cade, W. (1975-12-26). "Acoustically Orienting Parasitoids: Fly Phonotaxis to Cricket Song". Science. 190 (4221): 1312–1313. doi:10.1126/science.190.4221.1312. ISSN 0036-8075.
  18. Adamo, S.A.; Robert, D.; Hoy, R.R. (March 1995). "Effects of a tachinid parasitoid, Ormia ochracea, on the behaviour and reproduction of its male and female field cricket hosts (Gryllus spp)". Journal of Insect Physiology. 41 (3): 269–277. doi:10.1016/0022-1910(94)00095-x. ISSN 0022-1910.
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