Lepidoptera genitalia

About: Lepidoptera genitalia is a research topic. Over the lifetime, 10114 publications have been published within this topic receiving 78876 citations. The topic is also known as: Uncus.

Biology of Trichogramma galloi and T. pretiosum (Hymenoptera: Trichogrammatidae) reared in vitro and in vivo

Abstract: The life cycle and parasitization of Trichogramma galloi Zucchi and T. pretiosum Riley were studied on natural and factitious hosts, and on artificial diets. Eggs of sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Pyralidae), and tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used as natural hosts of T. galloi and T. pretiosum , respectively. Eggs of Mediterranean flour moth, Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae), were used as factitious host for both parasitoids. T. galloi was reared in vitro on a diet of 70% hemolymph of larvae of corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), 20% chicken egg-yolk, 10% bovine fetal serum, and 0.2% streptomycin. T. pretiosum was reared on a similar diet, with 5% H. virescens egg juice replacing 5% bovine fetal serum. The egg-adult development of T. pretiosum reared on the artificial diet was delayed, whereas developmental differences were not found for T. galloi reared on natural or artificial diets. Survivorship was also reduced for both parasitoids reared on artificial diets. The parasitization and female longevity were reduced for parasitoids reared on the factitious host or artificial diets. No differences in adult size or in morphology of the genital apparatus were detected among parasitoids reared in vitro or in vivo; but wing and abdominal malformations occurred for parasitoids reared on artificial diets.

Extrinsic effects on fecundity-maternal weight relations in capital-breeding Lepidoptera

Abstract: Capital-breeding Lepidoptera depend for reproduction on metabolic resources assembled either entirely or primarily by their larvae, the former termed 'perfect' the latter 'imperfect'. Empirical evidence suggests that maternal size determines capital-breeder fecundity. The fecundity-maternal size relation is usually formulated as F = bW + a, where F is fecundity, W is final maternal size in units such as weight of newly transformed pupae, b is the slope, and a the intercept. Exhaustive search yielded 71 fecundity-maternal pupal weight relations for 41 capital breeders in 15 families, 58 of which, including 2 previously unpublished, were based on individual specimens, and 13 on grouped specimens. In 22 individual-specimen relations, cohorts divided into 2 or more subgroups were reared simultaneously at different temperatures, on different diets, or exposed to other extrinsic factors. These 22 'multiform' relations were compared with 36 'uniform' relations, and where possible cohort subgroups were compared. Pupal weights of cohort subgroups were affected much oftener than underlying slopes and intercepts. Individual-specimen slopes based on transformed data ranged 0.52-2.09 with a mean and standard error of 1.13±0.04, and slopes did not differ significantly among perfect, imperfect, multiform, and uniform categories. Despite the evident similarity, one relation does not apply to all capital breeders. Tradeoffs sometimes occur between fecundity, F, and mean egg weight, E. Reaction norms of fecundity and pupal weight across extrinsic-factor ranges were overwhelmingly congruent, which supports axiomatic status for the dependence of fecundity on capitalbreeder maternal size. Cooler rearing temperatures usually produced heavier female pupae and greater fecundities, a phenomenon of population dynamics interest. The two sides of practically all fecundity-maternal weight regressions are not statistically independent, in effect stating F = b(W + [F × E]) + a, which artificially inflates test statistics. Where desirable, the fully independent relation R = b(W [F × E]) + a can be used, where R is reproductive bulk, the mathematical product of F × E. Additional key words: temperature, diet quality, population dynamics 'Capital-breeding' describes Lepidoptera that depend for reproduction entirely or primarily on metabolic resources assembled by their larvae, in contrast to 'income-breeding', which describes those that depend for reproduction primarily or entirely on resources assembled by their adults (Boggs 1992, Miller 1996, Tammaru and Haukioja 1996). The gypsy moth, Lymantria dispar (L.) (Lymantriidae), is a capital breeder; the monarch butterfly, Danaus plexippus (L.) (Nymphalidae), an income breeder. In four butterfly income breeders in two families, income contributed ≥ 80% to fecundity, and capital ≤ 20% (Boggs 1997, Fischer and Fiedler 2001a). Based on sizes of superfamilies (Kristensen and Skalski 1999) and the extent to which income breeding is phylogenetically limited, probably ≈90% of extant Lepidoptera are capital breeders. Most outbreak Lepidoptera also are capital breeders (Miller 1996, Tammaru and Haukioja 1996). Capital breeders have an ovigeny index, OI, of 1 or >> 0, referring to the proportion of lifetime potential fecundity that consists of mature eggs at eclosion, whereas income breeders have an OI of 0 or <<1 (Jervis and Ferns 2004). Capital breeders with nonfeeding adults and OIs of 1 are here termed 'perfect', whereas those with OIs of >>0 whose adults may feed, but do so less than income breeders, are termed 'imperfect'. Maternal size is widely believed to determine fecundity in capital breeders (Leather 1988, Honek 1993). This belief derives not from experimentation but from long empirical observation. Direct fecundity-size relations occur in the lepidopteran phylogenetic sequence at least as early as Tineidae, the basal-most lineage of Ditrysia (Titschack 1922, Kristensen and Skalski 1999) and are probably part of the ground plan of Ditrysia, if not all Lepidoptera. This dependence implies that whatever influences maternal size may influence fecundity and its associated quality attributes, and thus population fluctuations. Fecundity can be a proxy for net reproductive rate (Carey 1993, Huey and Berrigan 2001) and has been implicated in capitalbreeder population fluctuations, as in Bupalus piniaria L. (Geometridae) (Klomp 1966), Bucculatrix pyrivorella Kuroko (Bucculatricidae) (Fujiie 1980), Leucoptera spartifoliella (Hübner) (Lyonetiidae) (Agwu 1974), and in capital-breeding Noctuidae (Spitzer et al. 1984). Traditionally, the relation between fecundity, F, and maternal weight, W, usually has been defined by linear regression as F = bW + a, where W refers to newly transformed pupae or newly eclosed adults, b is the slope, and a is the intercept or scaling parameter. Honek (1993) devised a fecundity-maternal weight relation for insects generally, as well as one for Lepidoptera, but he did not segregate capital breeders for special study nor exhaustively seek examples. Honek noted that weight appears on both sides of fecundity-maternal weight regressions, but that statistically independent measures of fecundity and maternal weight are practically 144144 JOURNAL OF THE LEPIDOPTERISTS’ SOCIETY nonexistent. In effect, such relations state that F = b(W + [F × E]) + a, where E is mean egg weight. The resulting nonindependence inflates test statistics and minimizes variation between response and explanatory variables. The practical usefulness of the traditional regressions is not necessarily impaired, but their statistics should not be used where strict independence between the variables is assumed. As discussed further on, a fully independent alternative relation emerged from this study. In any capital-breeder reared under homogeneous conditions, intrinsic effects alone will produce a direct relation between fecundity and maternal size. If a cohort of eggs or hatchlings is divided into subgroups, and each subgroup reared at a different level of an extrinsic factor, such as a different temperature, or on a different diet, then extrinsic effects are likely to be added to the intrinsic ones. Here I examine extrinsic effects on fecundity-maternal pupal weight relations during rearing of capital breeders. I focus on effects produced by different temperatures—as might occur during anomalous weather, or between microhabitats, or between generations or seasons—and by differing diet quality—as might occur on variably stressed or different kinds of foodplants, or on different kinds or amounts of adult nourishment. MATERIALS AND METHODS I assembled as many statistical fecundity-maternal weight relations as possible from a personal reference collection, electronic databases including Biosis, Biological Abstracts, and the Zoological Record, and from citations in references. Most relations were based on observations of specimens individually, a few on means of grouped specimens. Individual-specimen relations were admitted if based on samples numbering ≥ 20, grouped-specimen relations if based on groups numbering ≥ 5. No relations were excluded because of non-English text. In the 58 assembled individual-specimen relations, weights and fecundities were available in numerical form for three published and two unpublished ones (Table 1); weights and fecundities for the remainder were transcribed from enlarged photocopies of published scatterplots. Because transcription creates error—when one point covers another, for instance—I tested slopes of transcribed relations against corresponding slopes given in sources. A few departures were statistically significant, but most were not (F-tests, P = 0.99–0.009; median P = 0.76; n = 35). If P was < 0.25, I retranscribed, but in no case did retranscription change the outcome appreciably. I accepted scatterplots at face value despite minor inconsistencies, except that for Philosamia ricini Hutt. (Singh and Prasad 1987), which seemed too anomalous. In the 13 groupedspecimen relations, most weights and fecundities were available in numerical form (Table 2). Study relations consisted of perfect and imperfect groups and uniform and multiform subsets. 'Uniform' denotes homogeneous conditions of development expected to produce only intrinsic effects, and 'multiform' denotes heterogeneous conditions expected to produce extrinsic as well as intrinsic effects. I examined relations for extrinsic effects first by metaanalysis (Gates 2002) and second by comparing cohort subgroup relations provided in sources or obtained by deconstruction. A standardized maternal weight was desirable, and I chose fresh pupal weight. By the pupal stage metabolic resources for ovigenesis are in place. Moreover, pupal weight has been most often used in describing fecundity-size relations (42 of 58 relations in Table 1, 12 of 13 in Table 2), and explanatory variables based on weight outnumber those based on lineal dimensions such as forewing length and pupal diameter. I maximized the number of relations for study by converting female adult fresh weight, Wa, to fresh pupal weight, Wp, where Wp = Wa × 1.85, a factor based on four observations: (1) first-day female pupae of Malacosoma disstria (Hbn.) (Lasiocampidae) in a previously unpublished study averaged 1.98 times heavier than first-day adults (n = 30 weighings, paired); (2) a corresponding value of 1.81 for Epiphyas postvittana (Walker) (Tortricidae) (n >130 weighings, unpaired) (Danthanarayana 1975); (3) a corresponding value of 1.74 for Streblote panda (Hbn.) (Calvo and Molina 2005); and (4) a corresponding value of 1.67 for Cnephasia jactatana (Walker) (Tortricidae) (Ochieng'Odero 1990). Fecundity had been estimated in sources by various methods, all internally consistent and all accepted here. Methods included counting unlaid eggs in dissections of newly eclosed females, counting only eggs actually laid, and combining eggs laid with residual eggs in ovaries af