Oviposition behaviour and emergence through time of the small blue butterfly (Cupido minimus) in a nature reserve in Bedfordshire, UK

Abstract Climate change affects butterflies in many ways, influencing the timing of emergence and reproduction, habitat preferences, and behaviour. The small blue (Cupido minimus Fuessley, 1775) is highly specialised in its host plant requirements, feeding on the seeds of a single species, kidney vetch (Anthyllis vulneraria), on which the larvae occur singly to avoid cannibalism. The butterfly is likely to be vulnerable to temperature-related changes in oviposition, adult emergence, and host plant flowering times, and is, therefore, a good model species for investigating climate change-related impacts. Using 26 years of data from the national UK Butterfly Monitoring Scheme (1993–2019) from one nature reserve, and 4 years of targeted egg searches (2006, 2007, 2008, 2020) from three reserves in Bedfordshire, UK, we investigated the effects of local temperature on small blue emergence date and total abundance, whether flowerhead or local environmental characteristics predicted small blue oviposition behaviour, and whether this changed between years. Small blue adults emerged on earlier dates over time, and earlier in years with higher maximum February temperatures. Total adult abundance was not predicted by monthly temperatures or total abundance in the previous year. Oviposition behaviour was broadly consistent across years, with egg presence more likely and egg abundance higher on kidney vetch flowerheads that were taller than the surrounding vegetation, and surrounded by taller vegetation and fewer mature flowerheads. The effect of solar radiation differed between years, with a negative effect on the probability of egg presence in 2007 and 2008, but a positive effect in 2020. Egg abundance per flowerhead was highly variable between years, with 2006 having four times more eggs per flowerhead than other years. This was likely driven by high adult abundance in 2006, which could have increased competition for flowerheads. Implications for insect conservation Our results indicate that management for greater availability of taller kidney vetch amongst taller vegetation would encourage small blue oviposition on a greater number of flowerheads, providing a possible means of reducing competition and increasing larval survival, and that this would be effective despite variation in adult abundance between years. The high level of competition we observed in the year with the highest adult abundance indicates that higher numbers of host plants should be encouraged to reduce competition and larval cannibalism in peak years, increasing the likelihood of long-term population persistence and growth.

Butterflies (Lepidoptera: Papilionoidea) of the island of Korčula, Croatia

A study of the butterfly fauna of the Croatian island of Korčula is presented. Fieldwork was carried out from 2011 to 2017, during several visits in different vegetation seasons, from the end of April until November. Altogether, 53 species were recorded during the survey, including 21 new records for the island. Along with literature records, 60 butterfly species have so far been recorded on Korčula. When compared with other Adriatic islands, only Cres, Lošinj, Krk and Brač have more butterfly species than Korčula. In general, the number of species, as well as species abundance, was very high in most localities, indicating the long-term persistence of suitable habitats on the island. Records of rare species such as Iolana iolas, Cupido minimus, Aglais urticae, Satyrus ferula and Pyrgus armoricanus present important extensions of their known ranges on the islands and in Dalmatia.

I Lepidotteri Ropaloceri della Montagnola Senese (Siena, Toscana meridionale) (Lepidoptera)

Una ricerca ventennale (1991-2011) sulla ropalocerofauna della Montagnola Senese, un Sito d’importanza Comunitaria della Toscana meridionale, ha permesso di accertare la presenza di 97 specie, (15 Hesperiidae, 3 Papilionidae, 13 Pieride, 31 Lycaenidae, 35 Nymphalidae). Le specie più significative sono Pyrgus sidae (Esper, 1784), Carcharodus lavatherae (Esper, 1783), Lycaena thersamon (Esper, 1784), Satyrium w-album (Knoch, 1782), Cupido minimus (Fuessly, 1775), Phengaris arion (Linnaeus, 1758), Polyommatus daphnis (Denis & Schiffermuller, 1775), Polyommatus hispanus (Herrich-Schaffer, 1851) e Brenthis hecate (Denis & Schiffermuller, 1775), entità di valore conservazionistico o di interesse biogeografico. Particolarmente interessanti risultano C. minimus e P. daphnis poiché in nessun’altro comprensorio della Toscana meridionale risultano così abbondanti come nella Montagnola Senese. Gli habitat di maggior interesse sono le praterie xeriche, le garighe e gli ex coltivi (“insule coltivate”) che ospitano oltre i tre quarti delle specie note per la Montagnola Senese. Anche le leccete, tuttavia, rivestono una certa importanza dal momento che ospitano entità di pregio faunistico e conservazionistico come S. w-album e Charaxes jasius (Linnaeus, 1767). La principale minaccia è rappresentata dall’attività estrattiva che determina perdita di habitat. La riduzione o la riprogrammazione delle attività di estrazione insieme alla tutela di praterie, garighe e “insule coltivate” si configurano come azioni fondamentali per garantire la sopravvivenza della ropalocerofauna della Montagnola Senese.