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RECORDS NOTEBOOK Containing this month:
The Lowestoft District has become host to two unwelcome visitors this autumn. The first is the Harlequin Ladybird Harmonia axyridis. Since the first record in 2004, numbers have increased to well into double figures at all sites so far recorded. In Gunton Wood Lowestoft (TM542958) it took only 30 minutes to collect 21 specimens. 14 were of the type succinea, 19 black spots on orange/red body and seven were of the type spectabilis four spots on a black body. Only one native seven- spot ladybird was found. I have recently had reports of Harlequins in houses including my parent’s house in Kessingland and many friends’ houses in Lowestoft. We will monitor the spread of this ladybird to look for its impact on the native species in the spring. The second alien is the recent discovery of the Horse Chestnut Leaf miner Cameraria ohridella, which is attacking the leaves of the Horse chestnut trees, causing premature leaf fall and other problems. The tree warden in Oulton Village has reported several trees affected, although the Gisleham tree warden reports no problems. I have since found ‘mines’ in Gunton Wood and Corton Wood so it seems another unwelcome visitor has come to stay. There is a fungus affecting Horse Chestnut leaves but the mines have small maggots in and once your eye is in they are so easy to find. Colin Jacobs
As butterfly seasons go, 2005 has been unexceptional in most respects, yet two rare aberrations turned up in Suffolk. This note records the sightings of what appear to have been naturally arising wild insects. They are forms of the Small Copper and the Small Tortoiseshell; both were photographed, and their images displayed at the SNS members’ evening on 23 rd November 2005. Lycaena phlaeas f – alba. Aglais urticae ab. conjuncta.
During the last 24 hours of its larval existence and the first 48 hours of the pupal stage, the natural process of metamorphosis may be disrupted by an extreme shock of either hot or cold. This shock can inhibit the normal process of “differentiation” during which organic chemicals create the colouration of the wing scales. This process is progressive, with the forewings differentiating before the hind wings. In nature, such a shock could be created when a larva settles for pupation in a shady situation and a falling tree (or some such) removes the shade, leaving the pupa in direct sun. It needs to reach about 44°C to create these aberrations, a temperature that also sterilises the insect; an extra degree or two is fatal. Most of our knowledge comes from experiments in captivity. There is a range of aberrations; one level of exposure creates semi-ichnusoides, a little more fuses all three black blotches along the costa of the forewing to create ab. conjuncta, and the most extreme exposure produces an almost entirely melanic form known as ab. osbornii. Ken Medler’s specimen was the middle form, conjuncta. The three forms vary in rarity, semi-ichnusoides is rare, conjuncta even more rare, and osbornii the rarest. It is difficult to discover how frequently any of these occur in the wild. Very few are to be found in museum collections, although the Hope Collection does include the results of the Merrifield experiments. Anyone interested in these aberrations can now make an on-line inspection of the Natural History Museum’s Cockayne Collection at: www.nhm.ac.uk/entomology/cockayne where similar forms of Large Tortoiseshell, Peacock, Red Admiral and Painted Lady may also be found. One sighting of ab. semi-ichnusoides in Suffolk took place in September 2003, when Richard Stewart found one in his Ipswich garden (Stewart, 2004) although this butterfly remained just out of photographic range. No earlier Suffolk records have been traced. Given the millions of Small Tortoiseshells over the years, it seems fair to judge these aberrations extremely rare in the wild. Since the heat shock also renders the butterflies sterile, each example is a one-off, and not a genetic strain. ReferencesBailey K. E. J., 2005, Personal Communication. Collins, E. J., 2005, Personal Communication. Medler, K., 2005, Personal Communication. Stewart, R. G. 2004, The Small Copper ab. careuleopunctata, Ruhl in Suffolk, 2003. The Small Tortoiseshell ab. semi-ichnusoides: a Suffolk sighting. Trans Suffolk Nat. Soc. 40:110. Thomas J. & Lewington, R., 1991. The Butterflies of Britain & Ireland, Dorling Kindersley. Rob Parker, 66, Cornfield Rd, Bury St Edmunds, IP33 3BN
The stag beetle is listed in Annex II of the EC Habitats Directive. In the UK it is classed as Nationally Scarce (Notable b) and is listed on Schedule 5 of the Wildlife and Countryside Act, making it illegal to trade in the species. It is a Priority Species in the UK Biodiversity Action Plan (UK BAP). Management of the UK BAP is led by the Peoples’ Trust for Endangered Species (PTES). The lead partner for the Stag Beetle Biodiversity Action Plan in Suffolk is Colin Hawes of the PTES Stag Beetle National Steering Group.
Stag Beetle UK Biodiversity Action Plan (BAP) targets The current targets (revised 2001) are: To achieve these aims, stag beetle populations need to be monitored. This requires targeted surveys and recording to be undertaken at
Public response 2005 A request published in the East Anglian Daily Times (28 th June) and Advertiser (31 st June) for readers to report sightings of stag beetles brought a tremendous response, with 240 people telephoning, e-mailing or writing to the author. Over 800 stag beetles were reported, excluding those recorded in the road casualty survey, details of which are given below (Table 1). Several respondents also volunteered to take part in the 2006 Stag Beetle Road Casualty Survey. New locations were revealed for this species at Creeting St Mary (2005), Coddenham (1965), Framlingham (2004), Leavenheath (2005), Reydon (1980) and Saxmundham (2005). Road Casualty Survey 2005 Belt-transect road casualty surveys (the term ‘road’ includes tracks and pavements) were carried out principally in Suffolk. Data collected to date suggest that large numbers of stag beetles become the victims of pedestrian and vehicular traffic. They also suggest that this method of monitoring is suitable for indicating presence or absence of the insect, abundance, trends in abundance and a road casualty sex ratio. Summary of results Table 1
It is pleasing to report that eight surveyors ensured that the stag beetle corpses collected were sent for further analysis (White Admiral 60 p36). Table 2
The mean ratio of female to male road casualties referred to in Table 2 is 2.9: 1. The mean ratio of female to male live stag beetles (Table 2) observed along the same transects whilst looking for road casualties is 2.2: 1. Stag beetles produce equal numbers of female and male offspring (Hawes, 2005). However, female stag beetle road casualties on average outnumber those of males by approximately 3:1. A possible explanation for this difference lies in the behaviour of the two sexes. Although both males and females can fly, females spend most of their active time on the ground searching for a suitable place to lay their eggs, whereas males spend the greater part of their active time flying in search of females. Thus females are more likely to be found crawling on footways and highways than males, where they are vulnerable to passing pedestrian and vehicular traffic. Stag beetle road casualties are bad news for this scarce species. The loss of each female usually means the loss of up to 30 eggs and thus 30 potential offspring. Recording 2006 Records of stag beetle sightings are needed from anywhere in Suffolk, even if they have been recorded previously at a particular location. Records noting the presence or absence of stag beetles are especially required from the following areas: Road Casualties 2006 Volunteers are urgently needed to survey a road (track or footway) for stag beetle casualties, especially at stag beetle hotspots, such as Ipswich, Woodbridge and Hadleigh. As in previous years, this involves regularly walking the same route (approx. 500 metres) and counting the beetles seen.A booklet giving further details can be obtained by contacting Colin Hawes at 3 Silver Leys, Bentley, Ipswich IP9 2BS Radio-tracking 2006 Little is known about the distances stag beetles travel or their ability to disperse and colonise new areas, especially in residential zones. To date, capture-mark-recapture fieldwork data suggests that females stay relatively close to the site from which they emerge, whilst males often fly 50 m or more in search of females. However, capture-mark-recapture experiments have not provided the detailed data required for the development of a fully effective stag beetle conservation strategy. Therefore, this year radio telemetry (equipment funded by English Nature) will be used to track beetles of both sexes from day to day over a period of at least 10 days. Bioacoustics 2005-2006 Until recently, access to larvae has been dependent on the accidental disturbance of their underground habitat. Deliberate digging to find larvae has been avoided as it destroys their habitat and usually kills several of their number. Recently, however, collaboration with the Electronics Department at the University of York has led to the loan of equipment, which is being used to find and identify stag beetle larvae in situ by detecting the stridulation sounds that they make. Soil temperatures Given the apparent association between soil type, accumulated (air) temperatures, residential zones and stag beetle distribution, soil temperature would seem to be a vital area for further study. Soil temperature is likely to affect larval growth and development, the length of the pupal phase and quiescence of overwintering adults, as well as act as a cue for emergence above ground. Soil temperatures will be measured at a number of sites (e.g. in residential areas, in the open countryside, in stag beetle breeding habitat) over the next three years. Acknowledgements Thanks to all 240 members of the general public who provided over 800 records of stag beetles and several new sites for the insect. Thanks, too, to David Green (EADT Environment Correspondent) for providing the timely publicity. A special thank you, also, to the stag beetle road casualty volunteers, some of whom have been involved in this survey over several years: Guy Ackers, Chris Austick, Janet Baker, Janet and Jim Buis, Bob Deex, Chris Ellis, Maria Fremlin, John Glazebrook, Dr Douglas Harper, Moray Henderson, Rosemary Milner, Nicola Moxey, Sian Scott, John Tombs, Mark Usher, Paul Vereycken, Mark Wagstaff, David Walker, Peter Winter and M. Willbourne, for providing valuable monitoring data and stag beetle corpses for studies taking place at RHUL. I am indebted, too, to Bentley residents and to the head teacher at Bentley primary school who once again allowed me to set insect traps in their gardens, orchards and grounds. Finally, it is my pleasure to acknowledge the PTES, Forestry Commission, Suffolk Naturalists’ Society and English Nature for the financial support they have given to this project, and thank, too, Dr Dave Chesmore and Ian Farr (University of York), Dr Jason Chapman (Rothamsted Research) and Dr Alan Gange (Royal Holloway University of London) for their advice and assistance. Reference Hawes, C. J. 2005. The stag beetle Lucanus cervus L. (Coleoptera: Lucanidae) in the county of Suffolk ( England): distribution and monitoring: 51-67. In: Barclay, M.V.L. and Telnov, D. (eds). Proceedings of the 3 rd Symposium and Workshop on the Conservation of Saproxylic Beetles, Riga/Latvia, 7 th - 11 th July, 2004. – Latvijas entomologs, Supplementum VI.
Colin Hawes In Flower Around Framlingham,
94 species Alasdair Aston |
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© 2006 Suffolk Naturalists' Society
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