Eur. J. Entomol. 111 (4): 501-511, 2014 | DOI: 10.14411/eje.2014.062

Growth and development in a lepidopteran with variable instar number, Pseudocoremia suavis (Geometridae), under standard rearing conditions and when parasitised by Meteorus pulchricornis (Hymenoptera: Braconidae)

Emma I. BARRACLOUGH, Elisabeth P.J. BURGESS, Aliesha M. KEAN, Louise A. MALONE
The New Zealand Institute for Plant & Food Research Limited, Mt Albert Research Centre, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand; e-mails: emma.barraclough@plantandfood.co.nz; elisabeth.burgess@plantandfood.co.nz; louise.malone@plantandfood.co.nz; aliesha.kean@hotmail.com

Though extra instars are often associated with poor conditions and thought to be a compensation for a low growth rate, the reasons why they are necessary, and for variable instar number existing under standard rearing conditions, are not yet clear. In standard rearing conditions, approximately half of Pseudocoremia suavis larvae had five instars (Type I larvae), and half six instars (Type II larvae). Type II larvae took longer to pupate and reached higher pupal weights than Type I larvae. The extra instar was not related to sexual size dimorphism; Type II larvae were not more likely to be females. Females of both Types pupated later than males and had higher pupal weights; this weight gain was achieved wholly via an extended final instar. Relative growth rates (RGR), instar durations and larval weights on weigh days were otherwise the same for both sexes. For most of the larval period, Type II larvae had lower RGR and lower weights than Type I larvae. They also had shorter 3rd, 4th and 5th instars than Type I larvae, and the estimated weights at each moult were significantly lower. The Types are discussed in terms of being, in species with weight thresholds for pupation, not optional "strategies" involving different critical weight ratios for larval moults, but as an inevitable consequence of physiological timing constraints upon reaching the critical weights for larval moults causing large variation in size after the moult. Small larvae may then need an extra instar to reach pupation. When parasitised in the second instar by Meteorus pulchricornis, P. suavis larvae produced parasitoids in either their fourth (4th instar emerging (IE)) or fifth instar (5th IE). The estimated moulting weights at each instar of 4th IE and 5th IE hosts were very similar to those of Type I and Type II unparasitised larvae respectively, which, together with similarity of instar duration patterns, is strongly suggestive of Types being present within parasitised larvae. The proportion of 5th IE hosts in the much slower-growing parasitised treatment was greater than the proportion of Type II larvae in the unparasitised treatment, as might be expected if Type II is associated with lower RGR. The lack of further Types appearing is consistent with extra instars being a compensation for small weight after the moult rather than low RGR per se.

Keywords: Geometridae, Pseudocoremia suavis, Hymenoptera, Braconidae, Meteorus pulchricornis, variable instar number, critical weight ratio, critical weight, developmental polymorphism, instar number, instar duration, gate

Received: November 5, 2013; Accepted: June 10, 2014; Prepublished online: August 15, 2014; Published: October 1, 2014

Download citation

References

  1. Alma P.J. 1975: A Study of Captures of Noctuidae and Geometridae in a Light-trap at the Forest Research Institute, Rotorua. Forest Entomology Report No. 43, New Zealand Forest Service, Forest Research Institute, Rotorua, 35 pp
  2. Azidah A.A. & Sofian-Azirun M. 2006: Life history of Spodoptera exigua (Lepidoptera: Noctuidae) on various host plants. - Bull. Entomol. Res. 96: 613-618 Go to original source...
  3. Barata C., Baird D.J. & Soares A.M.V.M. 2001: Phenotypic plasticity in Daphnia magna Straus: variable maturation instar as an adaptive response to predation pressure. - Oecologia 129: 220-227 Go to original source...
  4. Barraclough E.I., Burgess E.P.J., Philip B.A., Wohlers M.W. & Malone L.A. 2009: Tritrophic impacts of Bt-expressing transgenic pine on the parasitoid Meteorus pulchricornis (Hymenoptera: Braconidae) via its host Pseudocoremia suavis (Lepidoptera: Geometridae). - Biol. Contr. 49: 192-199 Go to original source...
  5. Berndt L., Brockerhoff E.G., Jactel H., Weis T. & Beaton J. 2004: Biology and rearing of Pseudocoremia suavis, an endemic looper (Lepidoptera: Geometridae) with a history of outbreaks on exotic conifers. - N. Z. Entomol. 27: 73-82 Go to original source...
  6. Berry J.A. 1997: Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae: Euphorinae), a new record for New Zealand. - N. Z. Entomol. 20: 45-48 Go to original source...
  7. Blackman V.H. 1919: The compound interest law and plant growth. - Ann. Bot. 33: 353-360 Go to original source...
  8. Burgess E.P.J., Barraclough E.I., Kean A.M., Walter C. & Malone L.A. 2011: No impact of transgenic nptII-leafy Pinusradiata (Pinales: Pinaceae) on Pseudocoremia suavis (Lepidoptera: Geometridae) or its endoparasitoid Meteorus pulchricornis (Hymenoptera: Braconidae). - Environ. Entomol. 40: 1331-1340 Go to original source...
  9. Burgess E.P.J., Kean A.M., Barraclough E.I., Poulton J., Wadasinghe G., Markwick N.P. & Malone L.A. 2014: Evaluation of the field impacts of simulated Bacillus thuringiensis-transgenic Pinus radiata on nontarget native Lepidoptera and their natural enemies in a New Zealand plantation forest. - Agric. Forest Entomol. 16: 63-74 Go to original source...
  10. Callier V. & Nijhout H.F. 2011: Control of body size by oxygen supply reveals size-dependent and size-independent mechanisms of molting and metamorphosis. - Proc. Nat. Acad. Sci. USA 108: 14664-14669 Go to original source...
  11. Casimero V., Tsukuda R., Nakasuji F. & Fujisaki K. 2000: Effect of larval diets on the survival and development of larvae in the cotton bollworm, Helicoverpa armigera Huebner (Lepidoptera: Noctuidae). - Appl. Entomol. Zool. 35: 69-74 Go to original source...
  12. Davidowitz G., D'Amico L.J. & Nijhout H.F. 2004: The effects of environmental variation on a mechanism that controls insect body size. - Evol. Ecol. Res. 6: 49-62
  13. Dugdale J.S. 1958: Structural characters of the larva of Selidosema suavis (Butler) (Lepidoptera: Geometridae, Subfamily Ennominae). - N. Z. Entomol. 2: 24-33 Go to original source...
  14. Esperk T. & Tammaru T. 2004: Does the 'investment principle' model explain moulting strategies in lepidopteran larvae? - Physiol. Entomol. 29: 56-66 Go to original source...
  15. Esperk T. & Tammaru T. 2006: Determination of female-biased sexual size dimorphism in moths with a variable instar number: The role of additional instars. - Eur. J. Entomol. 103: 575-586 Go to original source...
  16. Esperk T. & Tammaru T. 2010: Size compensation in moth larvae: attention to larval instars. - Physiol. Entomol. 35: 222-230 Go to original source...
  17. Esperk T., Tammaru T. & Nylin S. 2007a: Intraspecific variability in number of larval instars in insects. - J. Econ. Entomol. 100: 627-645 Go to original source...
  18. Esperk T., Tammaru T., Nylin S. & Teder T. 2007b: Achieving high sexual size dimorphism in insects: females add instars. - Ecol. Entomol. 32: 243-256 Go to original source...
  19. Etile E. & Despland E. 2008: Developmental variation in the forest tent caterpillar: life history consequences of a threshold size for pupation. - Oikos 117: 135-143 Go to original source...
  20. Fuester R.W., Taylor P.B., Peng H. & Swan K. 1993: Laboratory biology of a uniparental strain of Meteorus pulchricornis (Hymenoptera: Braconidae), an exotic larval parasite of the gypsy moth (Lepidoptera: Lymantriidae). - Ann. Entomol. Soc. Am. 86: 298-304 Go to original source...
  21. GenStat 2007: GenStat for Windows 10th Edition. VSN International, Hemel Hempstead, UK (www.vsni.co.uk/software/genstat)
  22. Godfray H.C.J. 1994: Parasitoids: Behavioral and Evolutionary Ecology. Princeton University Press, Princeton, xi + 473 pp
  23. Gould J., Venette R. & Winograd D. 2005: Effect of temperature on development and population parameters of Copitarsia decolora (Lepidoptera: Noctuidae). - Environ. Entomol. 34: 548-556 Go to original source...
  24. Greenlee K.J. & Harrison J.F. 2005: Respiratory changes throughout ontogeny in the tobacco hornworm caterpillar, Manduca sexta. - J. Exp. Biol. 208: 1385-1392 Go to original source...
  25. Harvey J.A., Sano T. & Tanaka T. 2010: Differential host growth regulation by the solitary endoparasitoid, Meteorus pulchricornis in two hosts of greatly differing mass. - J. Insect Physiol. 56: 1178-1183 Go to original source...
  26. Honek A. 1993: Intraspecific variation in body size and fecundity in insects - a general relationship. - Oikos 66: 483-492 Go to original source...
  27. Jensen J.G. & Cameron C.A. 2004: Development and kikuyu consumption of preimaginal Herpetogramma licarsisalis (Lepidoptera: Pyralidae) reared at temperatures between 15 and 25°C. - Environ. Entomol. 33: 1178-1184 Go to original source...
  28. Jones D., Jones G. & Hammock B.D. 1981: Growth parameters associated with endocrine events in larval Trichoplusia ni (Huebner) and timing of these events with developmental markers. - J. Insect Physiol. 27: 779-788 Go to original source...
  29. Kamata N. & Igarashi M. 1995: Relationship between temperature, number of instars, larval growth, body size, and adult fecundity of Quadricalcarifera punctatella (Lepidoptera: Notodontidae): Cost-benefit relationship. - Environ. Entomol. 24: 648-656 Go to original source...
  30. Kay M. 1983: Resistance of Douglas fir to Pseudocoremia suavis. - N. Z. J. Forestry Sci. 13: 46-52
  31. Kingsolver J.G. 2007: Variation in growth and instar number in field and laboratory Manduca sexta. - Proc. R. Soc. Lond. (B) 274: 977-981 Go to original source...
  32. Leonard D.E. 1970: Intrinsic factors causing qualitative changes in populations of Porthetria dispar (Lepidoptera: Lymantriidae). - Can. Entomol. 102: 239-249 Go to original source...
  33. Liu Y.H. & Li B.P. 2006: Developmental interactions between Spodoptera exigua (Noctuidae: Lepidoptera) and its uniparental endoparasitoid, Meteorus pulchricornis (Braconidae: Hymenoptera). - Biol. Contr. 38: 264-269 Go to original source...
  34. Liu Y.H. & Li B.P. 2008: Effects of Helicoverpa armigera (Noctuidae, Lepidoptera) host stages on some developmental parameters of the uniparental endoparasitoid Meteorus pulchricornis (Braconidae, Hymenoptera). - Bull. Entomol. Res. 98: 109-114
  35. Minitab 2010: Minitab 16 Statistical Software. Minitab Inc, State College, PA (www.minitab.com)
  36. Morita M. & Tojo S. 1985: Relationship between starvation and supernumerary ecdysis and recognition of the penultimate larval instar in the common cutworm, Spodoptera litura. - J. Insect Physiol. 31: 307-313 Go to original source...
  37. Nijhout H.F. 1975: A threshold size for metamorphosis in tobacco hornworm, Manduca sexta (L.). - Biol. Bull. 149: 214-225 Go to original source...
  38. Nylin S. & Gotthard K. 1998: Plasticity in life-history traits. - Annu. Rev. Entomol. 43: 63-83 Go to original source...
  39. Safranek L. & Williams C.M. 1984: Determinants of larval molt initiation in the tobacco hornworm, Manduca sexta. - Biol. Bull. 167: 568-578 Go to original source...
  40. Sehnal F. 1985: Growth and life cycles. In Kerkut G.A. & Gilbert L.I. (eds): Comprehensive Insect Physiology, Biochemistry and Pharmacology. Vol. 2. Pergamon Press, Oxford, pp. 1-86
  41. Singh P. & Moore R.F. 1985: Handbook of Insect Rearing. Vols I and II. Elsevier Science, Amsterdam, viii + 488 + viii + 514 pp
  42. Strand M.R. 1990: Characterization of larval development in Pseudoplusia includens (Lepidoptera: Noctuidae). - Ann. Entomol. Soc. Am. 83: 538-544 Go to original source...
  43. Tammaru T., Nylin S., Ruohomaki K. & Gotthard K. 2004: Compensatory responses in lepidopteran larvae: a test of growth rate maximisation. - Oikos 107: 352-362 Go to original source...
  44. Truman J.W. 1972: Physiology of insect rhythms: I. Circadian organization of the endocrine events underlying the moulting cycle of larval tobaco hornworms. - J. Exp. Biol. 57: 805-820
  45. Zondag R. 1956: Selidosema suavis. Control Plan No. 5. In: Forest Insect Survey Newsletter 5. Forest Research Institute, New Zealand Forest Service, Rotorua, pp. 21-34