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ŠUMARSKI LIST 3-4/1977 str. 42     <-- 42 -->        PDF


On the denomination of generations of polyvoltine insect species

The term generation , which has a number of different meanigs, denotes
in entomology most frequently the following:

1. a population of all individuals of a species of approximately the same
2. a certain developmental stage of a group of individuals of a given
3. the average span of time necessary for a species to complete its developmental
In the polyvoltine insect species individual generations within a one-year
(or sometimes tworyear) developmental cycle (in the sense of the definition
given above under 1.) differ alway more or less from each other and may
therefore be denoted by specific, fixed manes, ordinal numbers, or a combination
of both. The simplest and most frequent in practice is their denomination by
ordinal numbers. Here, however, arises the problem of which generation should
be denominated as the »first«: the one which first begins its development in
a calender year (the first complete generation), or that which appeared first
in that year. In the literature — both Yugoslav and foreign — the approach
to this problem is variegated, a fact often leading to ambiguity and misunderstanding.

An analysis of the developmental cycles of numerous polyvoltine species
speaks in favour of the first solution, and, in the author´s opinion, such denomination
of generations should be applied uniformly and consistently to all polyvoltine
species in order to avoid the possibility of misinterpretation.

Also, the polysemic character of the word generatio n may be one
of the reasons for the terminological confusion in cases of an inadequate use
of the term.

Primljeno 3. Ill 1977. Dr Ivan MIKLOS, dipl. ing. Sum.,
docent Šumarskog fakulteta u
Zagrebu, Šimunska c. br. 25.