Insect Systematics Research Articles

Systematics of injurious insects to turfgrass and some intruded-insects on turfgrass into Japan

Systematics of injurious insects to turfgrass and some intruded-insects on turfgrass into Japan

Careers in Systamatic Entomology

The following summarizes information on manpower distribution and needs in the field of insect systematics in North America. Included are points of view current amongst some insect systematists, some personal comments and suggestions, and references that may be of interest. First, it is evident that there are far fewer professionally employed insect systematists than the generally recognized need for their research and services would appear to warrant. Despite this recognized need, adequate professional positions have not been provided by the user community and insect systematists have been relatively unsuccessful in competing for funds for positions. Few positions wait to be filled. In fact, there has been keen competition for professional openings for atleast the past decade.

Report of the Standing Committee on Systematics Resources in Entomology: Proposal for a General Protocol for Submitting Specimens for Identification

The Entomological Society of America (ESA) Standing Committee on Systematics Resources in Entomology has as its primary responsibility the implementation of the ESA National Plan for Systematics Resources (see Bull. Entomol. Soc. Am. 20: 236–42). Progress is being made in attaining that long-term goal. Also, over the past two years the Committee has been pursuing various short-term projects that are of interest to a majority of the membership. These short-term projects have resulted in reports on a protocol for voucher specimens (Yoshimoto 1978, Bull. Entomol. Soc. Am. 24: 141–2), and reviews of charges for identification services (Chilson 1978, Bull. Entomol. Soc. Am. 24: 167–9). Future reports will review (1) the current situation regarding potential for relocation of collections and distribution of primary type materials, and of publications concerning needs for identification of specimens associated with ecological studies (Eldridge 1978, Bull. Entomol. Soc. Am. 24: 23–24), (2) Federal regulations affecting collecting, shipping, and receipt of specimens, (3) status of insect systematics training and manpower, (4) curricula in systematics training, and other matters.

A Historical Perspective on the Impact of the Type Concept on Insect Systematics

A Historical Perspective on the Impact of the Type Concept on Insect Systematics

Cuticular hydrocarbons of locusta, schistocerca, and Periplaneta, and their role in waterproofing

Hydrocarbons comprise 54% and 76% of the cuticular lipids extracted from the wings of L. migratoria and S. gregaria respectively. The hydrocarbon fraction of L. migratoria contains 17 n-alkanes ranging from C 14 to C 33 in chain-length, while that of S. gregaria contains 11 n-alkanes with chain-lengths ranging from C 22 to C 33. n-Nonacosane is the major consitituent of both fractions. n-Hentriacontane and n-heptacosane are major components of the L. migratoria and S. gregaria fractions respectively. The major branched alkanes of L. migratoria comprise 3-methylalkanes and mixtures of 9 + 13 + 15 + 17- methylalkanes . A dimethylalkane is also provisionally identified. The major branched alkanes of S. gregaria are mixtures of alkanes possessing one, two and possibly three methyl side chains. A comparison of the cuticular hydrocarbons of L. migratoria, S. gregaria and four other Orthopetera suggests that the hydrocarbon pattern of cuticular lipids could be a useful, additional character in insect systematics. Periplaneta americana resembles S. gregaria in having a high proportion of hydrocarbons in its cuticular lipid and in possessing a cuticle highly impermeable to water. Surface film balance studies show that a film of cockroach lipid spread on water does not form a tightly packed monolayer of polar molecules and it is suggested that the impermeability of the film to water is due to the formation of a heterogeneous monolayer, comprising mainly hydrocarbons, in which the molecules are optimally packed. A heterogeneous monolayer at the cuticulin surface could account for the high impermeability of cockroach cuticle to water, although frequent disruption of its molecular packing by newly secreted lipid makes this unlikely, and it is suggested that the outer regions of the cuticulin layer contain lipid and participate in the waterproofing of cockroach cuticle.

RECENT ADVANCES IN THE HIGHER SYSTEMATICS AND PHYLOGENETIC CONCEPTS IN ENTOMOLOGY

AbstractThis paper reviews recent work on the higher systematics of insects and summarizes the various phylogenetic concepts advocated. It is evident that there is considerable difference of opinion. This is likely to prevail since the fossil record is inadequate. It is suggested that a numerical analysis of the insects at the Order level might be profitable.

A Note on Trophic Complexity and Community Stability

A Note on Trophic Complexity and Community Stability

A Note on the Occurrence of Sipha agropyrella Hille Ris Lambers (Homoptera: Aphidae) in Manitoba

On October 16, 1956, during a routine monthly check of the Nurses Residence, Selkirk Mental Hospital, Selkirk, Manitoba, a professional exterminator noticed “thousands” of very small insects in a basement office. A number were submitted to the writer for identification and found to be aphids, which were later very kindly identified by W. R. Richards, Insect Systematics and Biological Control Unit, Ottawa, as Sipha agropyrella (H.R.L.). Richards stated (in litt.): “This is the first record of this species west of Ontario.” MacGillivray (1956) records the finding of this species in 1950 in New Brunswick as a new record for North America.

ECOLOGICAL FACTORS IN SPECIATION

The past decades have seen the gradual formulation of the theory of geographical speciation, principally based on work in the fields of the systematics of mammals, birds, insects, and mollusks. This theory 'postulates in bisexual animals a new species can develop only if a population, which has become geographically isolated from its parental species, acquires during this period of isolation characters which prorhote or guarantee reproductive isolation when 'the external barriers break down (Mayr, 1942). A number of workers in recent years have considered this statement an oversimplification. The omission of any reference in this description of the speciation process to the ecological factors-so vitally involved in the process of speciation-has also been objected to. Even though the importance of geographical speciation is universally admitted, there are a number of authors, particularly among the ichthyologists and entomologists, who believe in addition to geographical speciation there is another process of speciation, variously referred to as ecological or sympatric speciation. Thorpe (1945), for example, is inclined to consider in addition to geographical speciation there is a speciation process which is characterized by the fact that local differences of habit may be the starting point for the evolution of new species. It appears to me there is no real conflict between those authors who stress the ecological aspects of speciation, such as Stresemann (1943) and Thorpe (1945), and those who, like myself, have stressed the geographical aspects. This was pointed out by Timofeeff-Ressovsky (1943). The seeming differences are due partly to misunderstandings and partly to a different emphasis placed on various aspects of a single process of speciation. The field has suffered from looseness of thought and vagueness of expression, and it may therefore be ulseful to attempt a fresh analysis and possibly a synthesis of the two viewpoints. The principal obstacle blocking such synthesis up to now has been those authors who have emphasized the role of ecological factors in speciation generally accept sympatric speciation as an integral part of ecological speciation. To remove this difficulty, a special section (pp. 269-285) has been devoted to a discussion of sympatric speciation. It is more important, however, to determine the respective roles of geographical and ecological factors in speciation, and to find out whether they operate consecutively or concomitantly. The field has suffered particularly from the lack of a clear-cut Fragestellung. The result has been only few investigations have ever been undertaken which would give decisive answers to the unsolved questions. Most of the published studies sadly miss the crucial points. It is one additional object of this discussion to focus the attention of investigators on those aspects are in particular need of further study.