Observations on the Morphology and Bionomics of Rhabditis coarctata Leuck. occurring on Dung Beetles

1927 ◽  
Vol 5 (1) ◽  
pp. 33-46 ◽  
Author(s):  
Marjorie J. Triffitt ◽  
J. N. Oldham

During the pursuit of field work in the neighbourhood of Warwick in which the collection and examination of insects was involved, it was observed whilst carrying out dissections of dung-infesting beetles that several of them had attached to various parts of the exoskeleton collections of what were at first taken to be fungus spores. On close examination, however, these adherent bodies were discovered to be encysted nematodes which were using the beetles as carrying agents, whereby their transference to fresh dung, required for further development, would be assured.Our attention was drawn to a short note, written by Christie (1925), in which this author discusses the finding of what was either Rhabditis coarctata Leuck. or a closely related species on a number of species of dung beetles in America. With this information in mind, it was decided to culture the worms in order to follow out the life-cycle, determine the species, and make observations on the behaviour of the nematodes in relation to the insects on which they were found attached.

1963 ◽  
Vol 70 (1) ◽  
pp. 17-21
Author(s):  
Merrill H. Sweet

In the course of current work upon the biology and ecology of the Rhyparochrominae of New England, a new species of Ligyrocoris was discovered. The species runs in Barber's (1921) key to the couplet separating diffusus (Uhler) from sylvestris (L.), but is distinct from either species. While the new species is closely related to these species, it is also quite close to L. depictus which is separated out in a different part of Barber's key.These four closely related species are sympatric in New England, although they are markedly different in their overall distribution. The habitat preferences and life cycles of the species are quite different (Sweet, unpublished). The habitat of the new species described below is most unusual for the genus. The greater part of the type series was collected along the margin of a small pond where sedge clumps were standing in the water among occasional exposed rocks rather than in relatively dry fields or slope habitats where the other species occur. The species feeds upon the seeds of the sedge, Carex stricta Lam, and its life cycle is apparently adapted to that of the sedge, which fruits in late May and June. The insect becomes adult in mid-June and lays eggs until mid-July. The eggs remain in diapause over the summer and winter and hatch in May.


Biologia ◽  
2013 ◽  
Vol 68 (3) ◽  
Author(s):  
Jens Schirmel ◽  
Thomas Fartmann

AbstractCompetition is a basic type of interaction between species. Because complete competitors cannot exist in one habitat, closely related species must show at least slight differences in their biology or ecology. In the present study, we analyzed the habitat use of the two closely related bush-cricket species Tettigonia caudata and T. viridissima which often occur syntopically. The meso- and microhabitat use of males was compared in an agricultural landscape in NE Germany. Males of both species were found to use similar mesohabitats and to prefer dense and high vegetation. Microhabitats differed significantly in two aspects: Microhabitats of T. caudata had a higher proportion of herbs, while T. viridissima used higher song posts. These differences in microhabitats might explain the co-occurrence of the bush-crickets in open habitats. However, variation between the two species might also take place during other life-cycle stages such as during egg development.


Zootaxa ◽  
2012 ◽  
Vol 3434 (1) ◽  
pp. 31
Author(s):  
VERNER MICHELSEN

The European taxon Delia pruinosa (Zetterstedt) currently treated as one species is shown to represent a complex of several closely related species all characterized by the short antennnae, enlarged proboscis with strong, black prestomal teeth and a weak tibial setation. Biologically, all members of this Delia pruinosa species group may share the larval habit of living in seed capsules of various species of Silene L. (Caryophyllaceae). The number of species recognized in both sexes is presently raized from one to four: Delia pruinosa (Zetterstedt, 1845), D. judicariae (Pokorny, 1893), D. sileni sp. nov. and D. capdellae sp. nov. It is further documented that a few more species exist within this species group, but they are so far only known from female individuals. The known distribution of the Delia pruinosa species group includes Europe and western Anatolia.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rafael Molina-Venegas

AbstractAlthough there is growing interest in safeguarding the Tree of Life to preserve the human benefits that are directly provided by biodiversity, their evolutionary distribution remains unknown, which has hampered our understanding of the potential of phylodiversity indicators to evince them. Here, I drew on a global review of plant benefits and comprehensive phylogenetic information to breakdown their evolutionary distribution and thereby show why the commonly used Phylogenetic Diversity and Evolutionary Distinctiveness indicators can unequivocally help to preserve these natural services. Beneficial species clumped within phylogenetically overdispersed genera and closely related species often contributed very few and redundant benefits, suggesting that multiple plant lineages are required to maintain a wide variety of services. Yet, a reduced number of species stood out as multi-beneficial and evolutionarily distinct plants relative to both the entire phylogeny and the subset of beneficial species, and they collectively contributed a higher-than-expected number of records for most types of benefits. In addition to providing a clear mechanistic understanding for the recently proved success of Phylogenetic Diversity in capturing plant benefits, these findings stress the decisive role that conservation programmes aimed at protecting evolutionarily distinct taxa will play in safeguarding the beneficial potential of biodiversity for the future.


The Condor ◽  
2004 ◽  
Vol 106 (1) ◽  
pp. 191-196 ◽  
Author(s):  
Ernest J. Willoughby

Abstract Forty-five years ago Humphrey and Parkes (1959) introduced their system of nomenclature for molts and plumages (the H-P system). They claimed that their biologically neutral terminology, independent of the bird's life cycle events, could accurately reflect homologies of molts and plumages across a wide range of avian taxa. Soon, however, several investigators reported trouble adapting the terminology to unusual sequences of molts and plumages, and others expressed doubts that it could accurately reflect true phylogenetic homologies. Howell et al. (2003) reviewed these problems and proposed a modification of the original H-P system that identifies the juvenal plumage as the first basic plumage, and any postjuvenal plumages that are not repeated in later plumage cycles as formative plumages. By doing this, they solved the problem of adapting the original H-P system to plumages of the first year of life in many species. However, they have not overcome the arguments of Stresemann (1963) and Amadon (1966) that patterns of molting and plumage are so variable, and so subject to natural selection, that there is doubt that the H-P terminology can reveal phylogenetic homologies even among closely related species. Molting and plumage sequences within a clade comprising four species of the genus Carduelis confirm that within this limited grouping, molting and plumages are highly variable, and apparent homologies are not revealed in the H-P terminology as modified by Howell et al. La Terminología de la Muda y el Plumaje de Howell et al. (2003) Podría no Reflejar Aún las Homologías Resumen. Hace cuarenta y cinco años, Humphrey y Parkes (1959) introdujeron su sistema de nomenclatura para la muda y el plumaje (el sistema H-P). Ellos sugirieron que su terminología biológicamente neutra, independiente de los eventos del ciclo de vida de las aves, podría reflejar con exactitud las homologías de la muda y el plumaje a través de un amplio espectro de taxa. Sin embargo, poco después varios investigadores notaron problemas al adaptar la terminología a secuencias inusuales de muda y plumajes, y otros expresaron dudas en cuanto a si podría reflejar con exactitud las verdaderas homologías filogenéticas. Howell et al. (2003) revisaron estos problemas y propusieron una modificación del sistema H-P original que identifica el plumaje juvenil como el primer plumaje básico, y cualquier plumaje post-juvenil que no se repita en ciclos posteriores del plumaje como plumaje formativo. Haciendo esto, solucionaron el problema de adaptar el sistema H-P original a plumajes del primer año de vida de muchas especies. Sin embargo, no lograron resolver las críticas de Stresemann (1963) y Amadon (1966) de que los patrones de muda y plumaje son tan variables y tan propensos a ser afectados por selección natural, que es dudoso que la terminología H-P pueda revelar homologías filogenéticas, aún entre especies estrechamente relacionadas. Las secuencias de muda y plumaje al interior de un clado formado por cuatro especies del género Carduelis confirman que dentro de este limitado grupo, la muda y el plumaje son áltamente variables y que algunas homologías aparentes no son reveladas por la terminología H-P con las modificaciones de Howell et al.


Zootaxa ◽  
2021 ◽  
Vol 4903 (4) ◽  
pp. 493-500
Author(s):  
ROBERTO ARCE-PÉREZ ◽  
DANIEL REYNOSO-VELASCO

Two new species of Macrodactylus Dejean (Coleoptera: Scarabaeidae: Melolonthinae: Macrodactylini) from Mexico and Guatemala are described and illustrated: Macrodactylus miguelangeli new species from Mexico and Guatemala, and M. oaxacaensis new species from Mexico. With the descriptions of these two new species, the total number of species of the genus reaches 124. The characteristics of two closely related species are briefly discussed. 


2021 ◽  
Vol 9 ◽  
Author(s):  
Paul Coppo ◽  
Olivier Montreuil

The genus Cheironitis van Lansberge, 1875, currently contains 23 species from the Old World. During a survey for dung beetles in Jordan, specimens of an undescribed species were collected at the historical site of Petra. A new species of Cheironitis (C. petraensis sp. n.) is described from the historical site of Petra, Jordan, illustrated and compared with its most closely related species. This new species is reminiscent of the African species of Cheironitis living in savannahs and could represent a relictual species of the mid-Holocene climatic optimum.


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