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not clear frona the data collected. The duration os ovi position bovis ranged frona lminute to 48 minutes in tength Table l). The time period when ovi position was recorded most frequently was be- tween l9 00 hrs and 22 00 hi s. It appears, however, that ovi positing could occur atanytime bet ween clus k and dawn. Fui thermore, the majori ty of egg laying observations were made when the air temperature was around lo VC and Gortyna horetii was not recorded eg g laying when the temperature was below l09C Table l). The weather conditions most favoui able to ovi position appeared to be stili sc2 on Beati fori Scale), overcast, humid and relative ly mi ld. The preferred height forovi position by G. Dorelli was observed to be between 40 and 45 cm frona theground sui face Table l). The distance of ovi positing si ona the nearest larvat 1 ood plant ranged frona O cm to l50 cm Table l). However. the majori ty of observations were made within 30 cm of the clo sest smod plant. Va ultrastructure was examined using Scanning electron microscopy Figs4-6). Ova are spherical in sit ape with a si altened tot' and base and the fides have aribbed sui face structure. Flattened eggs are osten characteristic of Lepidoptera that glue their eggs together SCOBLE l99 ). The ova are approximate ly P00 pira in diameter and 350 μm in height. The ribbed sui face structures on the fides of ova are perforated by numerous aeropyles 2-3 μm in diameter). The ribs are approximate ly l0 pira in wid th. The roset te- like sculpture Fig. 6) of the chorion that suri Ouniis the micropylar area at the anterior pole of the eg g is characteristic of many species of Lepidoptera SCOBLE l 995). The micropyle is abo ut 6 μm in diameter.
An undet standing of the ovi positing strategy and requirements of G. borelliare important for the successsul manage irae ni and conservation of the VK population. The resulis frona this stud y suggest that G. horetii has a preferen ce for ovi positing on L. cithericia, then C re ens and A. elatius Fig. l) and not iis larvat 1 ood plant P. Docinale). Consequently G. boretii cloes not appear to be ovi position
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host specific. The preferetice for ovi positing on species of grass and not iis larvalmod plant is simi lar to related species, for ex ample Hydraecia immanis GIEBANK et a l. l 984. LEVI NE l 986) and H. micacea FRENCH et ah l9J3). This strategy may provide an advantage to the moth as the stems of P. Docinale do not provide a secure crevice within whicli the female can deposit her eggs. Any eggs laid onto P.
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United K ingdona appear to sitare more similarities with Hydraecia spp. than with species of Gortynia. HoweVer, where G. horetii occurs in forest steppe habitais in Hungary the stems of the larvat 1 ood plant appear to be the favoured ovi positionsi te L SZLO RONKAY pers. comm.). It is probabie, as G. horetii occurs with in adiversi ty os hahitais across central and solitheria Europe, that the OVi position requirements of the species will differ frona si te to site. Beliavi ourat observations of G. horetii ovi positing followed a sequence of
searching scra ling), sui face texture evaluation probing with the ovi positor) and finalty acceptance by probing into an appropriate crevice generat ly bet ween thestem and outer leaf sheath of a blade of grass) and depositing the eggs. The hostplanis for ovi positing ali, with one exception. have a relati Vely glabrous stem sui face texture. the exception being Holci S lanati X. The di ted grass siems chosen hyG. Dorelli for ovi position are generat ly more resistant to decay during the winter thus pro Viding a secure niche for ova. Ali species of grass on which G. Dorelli was observed ovi posit in g, possess a loose o uter leas sileat h. an ideat si te for ovi position
a similar observation is noted willi Hydriaecia immianis LEVI NE l 986)). As the preferred ovi position host for G. Dorelli is not the larvat mod plant in the United K in gilo m. it could be suggested that the critical phase of the life cycle is the abili ty of freshly emerged larvae to migrate frona over-wintering sites to thesmod plant. STEINER l 998) recorded G. boretii eg g laying, in Geraraany on grasssiems up to 5 m away frona the closest host plant. Howe ver in the United K ing dona. distances of greater than l. β m have not been recorde l. which may be due tot he differen ces in ei viro iamental and vegetational conditions at sites in Gerara any
and the VK RINGwOOD et al. 2002). The ova are deposited in large batches, resulting in the likelthood that many neo nate larvae will migrate to the sanae P. officinale plant to begin seed ing. It is probabie, however. that this migration accounts for a high levet of mortali ty with a substantiat proportion os larvae heing predated or not successsul ly locat ing a food plant. It is stated in HAGGETT l98 l)that a maximum os just one pupa is mund with in each P. Os icinia te root stock which suggesis larvae ei ther disperse a considerable distance frona their hatchmgsi te or that a high levet os mortali ty occurs during the larvat stage. The major requirement of the mated se male is to recogni se the most appropri-ate o Ver-wintering habitat for the ova and the proximi ty of the habitat to the 1 ood plant. The densi ty of the smod plant anil sui round ing vegetation structure is there- fore important in providing a sui table en viron ment for ovi positing. The majori ty of
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Τahle 2. The generali sed phenology os Gortynia horetii and Peucedianum ossicintile in the V KG. horetii Time os year P. Osscintile Time of year
Adultearly Septembe mihi October Seed dispersalearly Septembe m id October
observations of ovi positing were in areas with a relative ly low densi ty of P. icinale anil a high densi ty os Elytrigia spp. There seems to he a clear selectivi tyfor ovi positing on Elytrigia spi' and Arrhenatherum and an under representati Onon FEStuca and Peucedanum. The reasons for the observed selectivi ty may relateio an adaptation of the moth to the habitat in the VK i. e. dense stands of Elytrigia Spp.). HoweVer, the collapse Os Peucedanum during the winter makes it a poorOVer-wintering si te for ova and the morphology of Festuca may not be fuit able as it
sponds with the part of the grass that supporis a loose otiter leaf sheath. The chosen height is above the Zone of senescence and decomposition os leas litter. hut is lowenough to be protected frona harsh winter weather. Many of the siles that supportG. Dorelii populations in Brita in occur along sea walis, and as part of the ira a inte- nance of sea defences they are mown annually. Is G. Dorelli requires grass of a certain height for ovi position, it is important to ensure that the culting of grass will en
able the grass to be at a sui table height for the moth cluring the flight period. Current ly, much of the sea wali supporting populations of the moti, is mown het weenthe end of August and the beginning of September. This period coincides with the pupation ad tali stage of G. Dorelli and the Howeringiseed dispersat stage of P. Gicinale Table 2). Therefore, not only is the current management regi me detrimental to the emergen ce and flight of the adult moth. hut it resulis in a s hori sward far shorter than the observed average ovi position height Table l). being avail ab leto the female for ovi position. Also. the period of cutting is before seed dispersalstage of P. Docinale Table 2) thus reduc ing the recruit ment rate of this plant. Elytrigia citherica was the most frequently observed ovi position host and this species is found only with in coastat habitats STACE l99J). However. G. Dorelii was also ob Sei Ved ovi positing on mur common grass species with a widespre ad distribution in the V K. Consequently it is thought that the ovi positing require-ments of G. Dorelli are not the reason why iis Britisti distribution is restricted tocoastat grassiand habitais in the solitheast of England . The main reason for the re-
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stricted distributiori of G. horetii seems to be the locat distributiori os Peucedanum. This study provides important information for the propo sed strategy os trans location of G. horetii colonies fui ther in land in the V K. away si ona the clanger of
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Globat warmin g, or climate change, is at present a popular Subjeci and hasbeen shown to affect biriis. Studies have deali main ly with changes in the geographic distribution of sonae species, their bellavi our and migration patiern BERT-HOLD l99l. ZELAMIEVICIUS i 99J). However, recent studies have shown that climate change may also have beneficiat effecis on the reproduction of hird s. Severat
In the current paper compari sons in laying initiation dates and c lutch si Zes of the Red backed Shrike in solitheria Poland are presented. The hypothesis that. likeother European species, the time of laying in Red backed Shrike should he earlier in recent years and clutch si Ze should also he bigger is tested.
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Laying dates obtained by analyses of nest-carcis are suscepti ble to hi ases is theobservation intens ity are not evenly spread over the breed ing season. WESOLOws Ri and CZAPULAK sl 986) indicated that the highest proportion of searching activi ty by collaborators of the Pol isti Nest Record Scheme occurred during May. However. in June 90R of the collaborators that were active in May were stili active. Theres ore, there was no need to analyse ille temporal differen ces between observ-