BR. J. BNT. NAT. HIST., 7: IW4 



on the chalk grassland adjacent to a mature beech and larch plantation, lor the other 

 two species, although their larval foodplants grow closer to the grassland traps than 

 the yew traps, the same could be said of many of the other 'delicate' species, and 

 it is not so obvious why these two species buck the trend. 



Among the robust species, the need for a sheltered flight corridor would not be 

 expected to be an important factor contributing to flight behaviour. In these species, 

 larval foodplants and roosting sites take precedence, and as none of the species feeds 

 on yew, the expectation is that these species should be trapped most frequently in 

 the grassland habitat. In the majority of cases where a bias is seen, this is the case, 

 but again there are exceptions, both Ochropleura plecta and Abrostola triplasia 

 apparently preferring the woodland habitat. In the latter species, finding a roosting 

 site may be a contributing factor, but this suggestion is very tentative. For O. plecta, 

 no convincing case can be made on the basis of any of the factors under consideration. 



The results contained herein broadly endorse Waring's (1989) findings that many 

 species of moth show habitat flight preferences. They suggest that for geometrid-like 

 species, but not for the more robust noctuid-like species, dense woodland may provide 

 a sheltered flight corridor, a factor alluded to by Waring in respect of Idaea biselata 

 and /. aversata. In the majority of cases, a sensible interpretation of the habitat biases 

 seen, based on current knowledge of the species in question, can be made. 



Acknowledgements 



We wish to express our thanks to the National Trust for permitting us to trap in 

 Juniper Bottom, and John Bebbington, the staff at Juniper Hall Field Studies Centre, 

 and the Field Studies Council, for providing facilities at Juniper Hall. Joanne Griffiths 

 typed the manuscript. Tamsin Majerus corrected the manuscript. Carys Jones was 

 supported by an SERC Quota Award. Michael Majerus is the recipient of an 

 NERC grant. 



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