If you need an accessible version of this item please contact JSTOR User Support

The Bionomics of the Wood Cricket, Nemobius sylvestris (Orthoptera: Gryllidae)

Peter D. Gabbutt
Journal of Animal Ecology
Vol. 28, No. 1 (May, 1959), pp. 15-42
DOI: 10.2307/2011
Stable URL: http://www.jstor.org/stable/2011
Page Count: 28
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
The Bionomics of the Wood Cricket, Nemobius sylvestris (Orthoptera: Gryllidae)
Preview not available

Abstract

1. The life history of the wood cricket, Nemobius sylvestris (Bosc.) has been studied in three populations in oak leaf litter in Devon. 2. Eggs laid August-November go into diapause until spring. 3. Instars 1-5, distinguishable by head-width, are present in summer and autumn; the fifth normally over-winters. Instars 6-8 are present in spring and reach maturity in August. 4. The insect breeds once a year and the generations are distinct. Since the life cycle lasts 2 years, there is annual cyclic isolation in the three populations studied. Different cycles have been reported elsewhere. 5. Growth-rates estimated from head-widths are significantly described by linear regressions. 6. Two periods of growth are separated by a winter pause. Growth-rate differences were insignificant between the sexes, significant between generations, but not correlated with temperature or rainfall. 7. The lengths of the stages, date of hatching and length of the hatching period were calculated. 8. Fecundity was estimated from field and laboratory experiments. 9. The sex ratio is unity. 10. Mortality data have been fitted to a logarithmic regression. Mortality is approximately 20% in the egg, 67% on hatching, and 11% over the first growing period. 11. The insect is omnivorous but eats mainly fallen oak leaves, which form the largest single component of the litter, with a peak in October-November and a minimum in July-August. 12. Predators ate the first five instars of Nemobius in laboratory experiments. 13. Predators reached their highest concentration, but not greatest numbers, when the Nemobius population was at its peak.

Page Thumbnails

  • Thumbnail: Page 
15
    15
  • Thumbnail: Page 
16
    16
  • Thumbnail: Page 
17
    17
  • Thumbnail: Page 
18
    18
  • Thumbnail: Page 
19
    19
  • Thumbnail: Page 
20
    20
  • Thumbnail: Page 
21
    21
  • Thumbnail: Page 
22
    22
  • Thumbnail: Page 
23
    23
  • Thumbnail: Page 
24
    24
  • Thumbnail: Page 
25
    25
  • Thumbnail: Page 
26
    26
  • Thumbnail: Page 
27
    27
  • Thumbnail: Page 
28
    28
  • Thumbnail: Page 
29
    29
  • Thumbnail: Page 
30
    30
  • Thumbnail: Page 
31
    31
  • Thumbnail: Page 
32
    32
  • Thumbnail: Page 
33
    33
  • Thumbnail: Page 
34
    34
  • Thumbnail: Page 
35
    35
  • Thumbnail: Page 
36
    36
  • Thumbnail: Page 
37
    37
  • Thumbnail: Page 
38
    38
  • Thumbnail: Page 
39
    39
  • Thumbnail: Page 
40
    40
  • Thumbnail: Page 
41
    41
  • Thumbnail: Page 
42
    42