202
N. WALOFF
maximum numbers of eggs at temperatures around ZO'C, i.e. in mean
summer temperatures in the British Isles. Yet another feature that may
be an adaptation to temperate climates is the prolonged period of emergence and hence the prolonged and overlapping occurrence of all the
immature stages in the field. This was particularly striking in Phytodectu and Sitona, where the oviposition periods of their populations
extended up to 120 days. Similarly, the developmental stages of
Arytaim spartii and of Lawoptera overlapped widely. In Considering
Phytodectn (Richards and Waloff, 1961) we discussed the implications
of a prolonged life history of a population as compared with that of
en individual and suggested that it is adaptive. It allows a species to
sample a full range of weather of an English Bummer, or more generally
of a temperate summer and it may be at least aa important that only
part of a population is at any time exposed to the full force of predation
and parasitism. It is true that the polyvoltine species, such as Arytaina
genistae and Apion immune achieve the same end by different means,
but most of the species that we have studied have interrupted life hiatories and overwinter in a state of facultative or obligatory diapause.
A CKN o w LE D o M E NTS
I should like to express my sincere thanks to the many postgraduates
who have worked at Silwood and who have given me permission to use
their theses in writing this Rurvey. The titles of ail the theses are included in the bibliography. The length of a list of names would begin
to rival that of the broom fauna, but in every case the work of the individual authors is acknowledged in the text. Finally, we all owe muoh
to the unobtrusive guidance and inspiration thst came from Profeseor
0. W. Richards.
REFERENCES
hgwu, S. I. (1967). Univ. London Ph.D. Thesis. The biology and population
dynamics of Leucgtera apadifoliella (Hb.) on Broom Sardhamnua ampariua.
Ammah-Att,oh, V. (1969). Uasiv. London M.Sc. "hais. A study of the hymenopteroum paramites of Miridae.
Anderson, N. H . (1962a). Tram. R . ent. SOC. Lond. 114, 67-96. Bionomica of six
species of Anthoeoris (Heteroptera, Anthoooridae) i n England.
Andemon, N. H. (196%). Ent. exp. appl. 5, 40-62. Growth and fecundity of
Anthoco7ie ~ p p .
reared on various prey (Heteroptera:Anthoooridm).
Anmombe, F. J . (1949). Biometrice 5. 166-173. Tho statistical malysh of inseot
counts bawd on the negative binomial distribution.
Bailey, N. T. J. ('1952). J . Anim. E d . 21, 120-127. Improvementa in the intarprctation of recapture data.
Baker, W. V. (1962). D.I.C. (Diploma Imperial College) Theaie. The biology of an
anystid mite (Actwine. Anystidm:Oudemans).
Belachowsky, A. (1949). Fatme FY, 50, Coleopt&w eoolytidea.
N. WALOFF
maximum numbers of eggs at temperatures around ZO'C, i.e. in mean
summer temperatures in the British Isles. Yet another feature that may
be an adaptation to temperate climates is the prolonged period of emergence and hence the prolonged and overlapping occurrence of all the
immature stages in the field. This was particularly striking in Phytodectu and Sitona, where the oviposition periods of their populations
extended up to 120 days. Similarly, the developmental stages of
Arytaim spartii and of Lawoptera overlapped widely. In Considering
Phytodectn (Richards and Waloff, 1961) we discussed the implications
of a prolonged life history of a population as compared with that of
en individual and suggested that it is adaptive. It allows a species to
sample a full range of weather of an English Bummer, or more generally
of a temperate summer and it may be at least aa important that only
part of a population is at any time exposed to the full force of predation
and parasitism. It is true that the polyvoltine species, such as Arytaina
genistae and Apion immune achieve the same end by different means,
but most of the species that we have studied have interrupted life hiatories and overwinter in a state of facultative or obligatory diapause.
A CKN o w LE D o M E NTS
I should like to express my sincere thanks to the many postgraduates
who have worked at Silwood and who have given me permission to use
their theses in writing this Rurvey. The titles of ail the theses are included in the bibliography. The length of a list of names would begin
to rival that of the broom fauna, but in every case the work of the individual authors is acknowledged in the text. Finally, we all owe muoh
to the unobtrusive guidance and inspiration thst came from Profeseor
0. W. Richards.
REFERENCES
hgwu, S. I. (1967). Univ. London Ph.D. Thesis. The biology and population
dynamics of Leucgtera apadifoliella (Hb.) on Broom Sardhamnua ampariua.
Ammah-Att,oh, V. (1969). Uasiv. London M.Sc. "hais. A study of the hymenopteroum paramites of Miridae.
Anderson, N. H . (1962a). Tram. R . ent. SOC. Lond. 114, 67-96. Bionomica of six
species of Anthoeoris (Heteroptera, Anthoooridae) i n England.
Andemon, N. H. (196%). Ent. exp. appl. 5, 40-62. Growth and fecundity of
Anthoco7ie ~ p p .
reared on various prey (Heteroptera:Anthoooridm).
Anmombe, F. J . (1949). Biometrice 5. 166-173. Tho statistical malysh of inseot
counts bawd on the negative binomial distribution.
Bailey, N. T. J. ('1952). J . Anim. E d . 21, 120-127. Improvementa in the intarprctation of recapture data.
Baker, W. V. (1962). D.I.C. (Diploma Imperial College) Theaie. The biology of an
anystid mite (Actwine. Anystidm:Oudemans).
Belachowsky, A. (1949). Fatme FY, 50, Coleopt&w eoolytidea.