Relative warp analysis to study morphological variations in the genital capsule of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Abstract

Neotropical Entomology 31(2): 217-224 (2002) Análise das Deformações Relativas no Estudo da Variação Morfológica na Cápsula Genital deTrichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) RESUMO ABSTRACT -The influence of the host on the morphology of the male genital capsule of Trichogramma pretiosum Riley was studied by geometric morphometric analysis. Specimens of the parasitoid obtained from 10 different Lepidoptera host species were used. Initially, landmarks were defined and Cartesian coordinates (x and y) for each landmark of the genital capsule of all specimens were obtained. The anatomic landmarks transformed to Cartesian coordinates were then analyzed by generalized orthogonal least-square procedure. Consensus configuration of the genital capsule for all specimens was obtained and partial and relative warps were determined. Fifteen landmarks generated 24 relative warps for each specimen. The ordination of the relative warps ( = 0), using shape components, separated T. pretiosum into four different hosts groups: (1 -Alabama argillacea (Hueb.), Helicoverpa zea (Bod.) and Diatraea saccharalis (Fabr.); 2 -Danaus plexippus erippus (Cramer), Hamadryas feronia (Linn.) and Spodoptera frugiperda (J.E. Smith); 3 -Anticarsia gemmatalis Hueb., Bonagota cranaodes Meirick and Diaphania sp. and 4 -Anagasta kuehniella (Zeller). The two first axes of the relative warps explained 83.0% of the total variation of the genital capsule shape of the specimens. The main difference was at the anterior region of the posterior extension of the dorsal lamina of the genital capsule. Although results obtained were initial and exploratory they have demonstrated that subtle shape differences in the male genital capsule can be detected by geometric morphometric analysis.

Ontogenetic trajectories and hind tibia geometric morphometrics of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera: Coreidae)

“…Insect size and growth has also been studied through the Brooks-Dyar rule, which assumes that the head will grow constantly and exponentially during successive molts (Dyar 1890; for a revision, see Daly 1985). Morphometrics constitutes a relevant tool for characterizing insect phylogenetic relationships (Pretorius & Scholtz 2001), intra-specific morphological variation (Querino et al 2002), sibling species and sexual dimorphism (e.g., Adams & Funk 1997), morphological adaptations (e.g., Moran 1986, Medeiros & Moreira 2002, and instar identification (Daly 1985). Within Insecta, previous studies of hemipterans have investigated static allometry in the hind tibia of Acanthocephala declivis guatemalana Distant, and their role in sexual selection (Eberhard 1998, also see Mitchell 1980), as well as studies concerning immature multivariate growth patterns (e.g.…”

Iberomeryx minor (Mammalia, Artiodactyla) from the Early Oligocene of Soulce (Canton Jura, NW Switzerland): systematics and palaeodiet

“…Regarding the geometric morphometric analysis, the method follows that proposed by Querino et al (2002) and Raia et al (2010). Traditional morphometric methods use linear distance measurements, which strongly correlate with size.…”

PRESERVING THE MONARCH BUTTERFLY (Danaus plexippusL.), PRESERVING NATURAL ENEMIES OF PEST

“…Desafortunadamente, la deforestación, la expansión de la frontera agrícola y el uso desmedido de herbicidas químicos han propiciado la merma de las poblaciones de asclepias, lo que a su vez amenaza las poblaciones de la mariposa monarca. Diversos estudios han documentado algunas causas de mortalidad de D. plexippus: depredadores como arañas (Araneae), chinches "asesinas" (Reduviidae), catarinitas (Coccinellidae) y ninfas de mántidos (Mantidae); parasitoides de larvas como las moscas taquínidas (Malcolm, 1994) y, aunque pobremente documentado, parasitoides de huevos como la avispita Trichogramma (Querino, Morales, & Zucchi, 2002).…”

“…Unfortunately, deforestation, expansion of the agricultural frontier and the excessive use of chemical herbicides have led to the decline of milkweed populations, which in turn threatens the populations of the monarch butterfly. Several studies have documented some killers of D. plexippus: predators such as spiders (Araneae), "assassin" bugs (Reduviidae), beetles (Coccinellidae) and nymphs of mantids (Mantidae); larvae parasitoids such as Tachinid flies (Malcolm, 1994) and, although poorly documented, egg parasitoids such as wasp Trichogramma (Querino, Morales, & Zucchi, 2002). …”