48 BR. J. ENT. NAT. HIST., 7: 1994 



The bottom of the valley is separated from the yew slopes by a sharply defined, 

 thick, mixed broad-leaf natural hedge. This provides a sharp habitat boundary between 

 the darkness inside the wood and the light of the open valley floor. The valley floor 

 is characterized by short, partly rabbit-cropped, chalk grassland. (For further details 

 of the vegetation types see Jones et al., 1993.) 



The traps used were 100-W mercury vapour discharge bulbs set on 'dustbin' traps. 

 They were set in pairs across the habitat boundary approximately 27 m apart and 

 with 77 m between each pair. 



Nine species with melanic forms were scored as typical, half-melanic, melanic or dark 

 banded according to morph phenotype. For Apamea monoglypha (Hufn.), which 

 displayed continuous variation, the morphs were graded from 1 to 5, lightest to darkest 

 respectively, using representative standard individuals of each class for comparison. 

 Similarly, for Hydriomena furcata (Thunb.), many different morphs were seen. They 

 were recorded according to colour (yellow, green or pink), pattern (speckled or banded), 

 strength of pattern and whether they were melanic, half-melanic or typical (absence of 

 large areas of black). For statistical analysis only melanic, half melanic and typical classes 

 were considered. The numbers of three species, N. pronuba, Craniophora ligustri 

 (D. & S.) and B. betularia were too small for any meaningful analysis to be performed 

 or deductions to be drawn, and results for these three are not included. 



Results and analysis 



The results for six species are given in Table 1. The data were analysed using 

 heterogeneity chi-squared analysis. (The chi-squared test determines the probability 



Table 1 . The numbers of moths of different forms of six species taken in yew woodland or 

 in chalk grassland at Juniper Bottom from 22.vi to 2.vii.l992. Data from the three traps set 

 each night in the yew woodland are totalled. Similarly the data from the three traps set in chalk 

 grassland each night are totalled. 



Peribatodes rhomboidaria 

 Yew woodland 

 Chalk grassland 



Typical 



85 

 46 



Melanic 



66 



8 





Total 

 151 



54 



Alcis repandata 

 Yew woodland 

 Chalk grassland 



Typical Half-melanic Melanic 

 47 97 16 

 43 39 11 



Banded 

 13 



5 



Total 



173 

 98 



Ectropis bistortata 

 Yew woodland 

 Chalk grassland 



Typical Half-melanic 



17 5 

 35 2 



Melanic 

 6 



5 



Total 



28 

 42 



Idaea aversata 

 Yew woodland 

 Chalk grassland 



Unhanded 



34 



17 



Banded 



13 



3 





Total 



47 

 20 



Apamea monoglypha 



Yew woodland 

 Chalk grassland 



Darkest ■* — Class 

 5 4 3 



1 10 



2 2 13 



2 

 4 

 9 



Lightest 



1 

 2 

 



Total 



17 

 26 



Hydriomena furcata 

 Yew woodland 

 Chalk grassland 



Typical Half-melanic 



22 5 

 27 8 



Melanic 



25 

 18 



Total 



52 

 53 



