Species Identification Of Larvae Research Articles

Detection of infection with Angiostrongylus vasorum (Nematoda, Strongylida) by PCR

Background The French heart worm Angiostrongylus vasorum is a parasitic nematode of the pulmonary arteries and heart of canines often with severe and in some cases fatal outcome. The diagnosis is based on detection and species identification of larvae in faeces which can be problematic in Veterinary praxis especially in cases with low excreting animals. A reliable technique is thus needed for correct diagnosis and estimation of the true prevalence of infection in a population as well as for monitoring and control campaigns.

Genetic identification and color descriptions of early life-history stages of Belizean Phaeoptyx and Astrapogon (Teleostei: Apogonidae) with Comments on identification of adult Phaeoptyx

Phaeoptyx and Astrapogon are represented in the Caribbean by six species (P. conklini, P. pigmentaria, P. xenus, A. alutus, A. stellatus, and A. puncticulatus). Species identification of larvae and juveniles is problematic because characters used to distinguish adults (e.g., patterns of pigmentation and numbers of gill rakers) are absent, incomplete, or difficult to discern in the young stages. Neighbor-joining trees derived from mitochondrial cytochrome oxidase 1 sequences (DNA Barcoding) were used to match early life stages and adults. Subsequent comparative analysis of preserved voucher specimens from which the DNA was extracted or digital color photographs of those specimens taken prior to preservation yielded sufficient information to separate all early life-history stages of Belizean Phaeoptyx and Astrapogon and provided additional information for field identification of adult Phaeoptyx. Patterns of chromatophores in fresh material, combined with patterns of melanophores, provide the easiest means of separating the life-history stages of Phaeoptyx. Larvae of Astrapogon species are morphologically very similar, and some differences in pigmentation detected among them may reflect different stages of development. Continued implementation of the DNA Barcoding methods and field protocol outlined herein should prove valuable in accurately identifying much more of the ichthyoplankton fauna of the Caribbean.

On the Roles of Morphological and Biochemical Criteria in Species Identification: An Example of Dragonfly Larvae of the Genus Aeschna

Dragonflies belong to the group of organisms with numerous well-differentiated species-specific characters at the adult stage, on the one hand, and a significantly smaller number or even the absence of such characters at the early ontogenetic stages. An example of the genus Aeschna is used to show difficulties in revealing morphological and biochemical characters allowing identification of larval dragonflies belonging to closely related species of the family. Distinct morphometric characters can be found only in late-instar larvae. The presence of species-specific proteins in the homogenates of thoracic muscles provides the possibility of using biochemical tests for species identification of larvae. Infestation by parasites has no effects on the biochemical parameters studied. Species identification of the early-instar dragonfly larvae is still problematic.