A comparison of larval survivorship in wild and introduced populations of the large copper butterfly (Lycaena dispar batavus)

Published source details Nicholls C.N. & Pullin A.S. (2000) A comparison of larval survivorship in wild and introduced populations of the large copper butterfly (Lycaena dispar batavus). Biological Conservation, 93, 349-358.
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This study is summarised as evidence for the following.

	Action	Category
	Manage wetlands or ponds by grazing or cutting to prevent succession Action Link
	Release captive-bred individuals to the wild Action Link
	Release captive-bred individuals to the wild Action Link
	Translocate to re-establish populations in known or believed former range Action Link
	Rear declining species in captivity Action Link

Manage wetlands or ponds by grazing or cutting to prevent succession

A replicated, site comparison study in 1996–1998 in nine fens in Overijssel, the Netherlands (Nicholls & Pullin 2000) found that fens cut in autumn or winter had lower large copper Lycaena dispar batavus caterpillar survival than uncut fens. The overwinter survival of large copper caterpillars in fens cut in autumn or winter (2–3%/year: 5/176 caterpillars found) was lower than in unmanaged fens (15–20%/year: 36/222 caterpillars found). In 1996–1998, four fens within a 3,500-ha lowland bog in the Netherlands were cut in autumn or winter, and five fens were not cut. In 1996–1997, wild large copper eggs were counted on every great water dock Rumex hydrolapathum plant encountered along a transect through each site. Plants were revisited three weeks later, and in April the following year, to record caterpillar survival.

(Summarised by: Andrew Bladon)
Release captive-bred individuals to the wild

A replicated, site comparison study in 1995–1998 in three fens in Norfolk, UK and nine in Overijssel, the Netherlands (Nicholls & Pullin 2000a, same study as Nicholls & Pullin 2000b) found that released, captive-bred large copper Lycaena dispar batavus caterpillars had lower overwinter survival rates than wild caterpillars. The overwinter survival of released captive-bred caterpillars in the UK (0–7%/year: 30/1,440 caterpillars found) was lower than the overwinter survival of a wild population in the Netherlands (19–42%/year: 41/139 caterpillars found). Post-winter survival to pupation of released captive-bred caterpillars in the UK was 49–56% (215/420 caterpillars found). A captive population of large copper was maintained for >25 years. From September–October 1995–1997, captive-bred caterpillars were released in seven 50 × 50 m plots across three sites in Norfolk. Five caterpillars were placed on each of 7–40 randomly chosen great water dock Rumex hydrolapathum plants/plot/year (total: 1,440 caterpillars). In April–May 1996–1998 plants were searched for surviving caterpillars. In April–May 1996 and 1997 a further 15–70 caterpillars/plot/year (total: 420 caterpillars) were released, and monitored through to pupation. In 1996–1997, at nine fens within a 3,500-ha lowland bog in the Netherlands, wild large copper eggs were counted on every water dock encountered along a transect through each fen. Plants were revisited three weeks later, and in April the following year, to record caterpillar survival.

(Summarised by: Andrew Bladon)
Release captive-bred individuals to the wild

A replicated, paired, site comparison study in 1997–1998 in a fen in Norfolk, UK (Nicholls & Pullin 2000b, same study as Nicholls & Pullin 2000a) found that released captive-bred large copper Lycaena dispar batavus caterpillars had lower overwinter survival rates than translocated wild caterpillars. The overwinter survival of released captive-bred caterpillars (1 of 95 caterpillars found) was lower than the overwinter survival of translocated wild caterpillars (8 of 95 caterpillars found). In September 1997, captive-laid eggs were obtained from a 25-year-old glasshouse-reared colony at Woodwalton Fen, and wild-laid eggs were collected from a 3,500-ha lowland bog in the Netherlands. Eggs from both sources were reared to overwintering in the laboratory. A total of 95 captive-bred and 95 wild caterpillars were placed on to 19 pairs of great water dock Rumex hydrolapathum (5 caterpillars/plant) in an open fen in Norfolk. In May 1998, after late flooding, surviving caterpillars were counted on each plant.

(Summarised by: Andrew Bladon)
Translocate to re-establish populations in known or believed former range

A replicated, paired, site comparison study in 1997–1998 in a fen in Norfolk, UK (Nicholls & Pullin 2000) found that translocated large copper Lycaena dispar batavus caterpillars had higher overwinter survival rates than released captive-bred caterpillars. The overwinter survival of translocated caterpillars (8 of 95 caterpillars found) was higher than the overwinter survival of released captive-bred caterpillars (1 of 95 caterpillars found). In September 1997, wild-laid eggs were collected from a 3,500-ha lowland bog in the Netherlands, and captive-laid eggs were obtained from a 25-year-old glasshouse-reared colony at Woodwalton Fen. Eggs from both sources were reared to overwintering in the laboratory. A total of 95 wild and 95 captive-bred caterpillars were placed on 19 pairs of great water dock Rumex hydrolapathum (5 caterpillars/plant) in an open fen in Norfolk. In May 1998, after late flooding, surviving caterpillars were counted on each plant.

(Summarised by: Andrew Bladon)
Rear declining species in captivity

A site comparison study in 1997–1998 in a laboratory in the UK (Nicholls & Pullin 2000) found that wild- and captive-laid large copper Lycaena dispar batavus eggs and caterpillars had similar survival in captivity. Both the survival to overwintering of wild-laid eggs (19 of 20 caterpillars), and the overwinter survival of these caterpillars (4 of 19 caterpillars), were statistically similar to the survival to overwintering (15 of 20 caterpillars) and overwinter survival (3 of 15 caterpillars) of captive-laid eggs. In September 1997, twenty wild-laid eggs were collected from a lowland bog in the Netherlands, and 20 captive-laid eggs were obtained from a 25-year-old glasshouse-reared colony at Woodwalton Fen. Eggs were reared to overwintering under controlled conditions (10 hours light, 14 hours dark, 20°C) in a laboratory. Immediately before overwintering, caterpillars were transferred to great water dock Rumex hydrolapathum pot plants and maintained in an overwinter environment (10 hours light, 14 hours dark, 5°C) for 20 weeks. Emergence was stimulated by increasing light by 15 minutes, and increasing temperature by 2°C, every two days for eight days, and survival was recorded.

(Summarised by: Andrew Bladon)