In February my friend Barry Yates, manager of the Rye Harbour Nature Reserve brought me a cormorant's nest in a dustbin so that I could breed out any insects therein. The nest consisted of a large bundle of sticks embellished with a few colourful pieces of rubbish. It was, of course, well impregnated with guano, fish waste and even had a dead and mummified young bird.
Bird's nests often contain many different invertebrates and some are rarely found elsewhere
Yesterday, 10 March 2009, I put the whole nest into an Owen emergence trap out in the garden in a position where the rain will wet it.
An apparently scarce gout fly (Siphunculina aenea) has been hatching out since the nest arrived (see picture below left). It is a rarely recorded Red Data Book fly (RDB3) and it has been bred in the past from bear's dung. During March there were many examples of the muscid fly Eudasyphora cyanella and the calliphorid Pollenia griseotomentosa. Both of these overwinter as adults and it therefore seems likely that they were simply using the nest as a hibernation site. Indeed, Pollenia spp. are, in their early stages, parasitoids of earthworms, animals that would hardly be found up a tree in a cormorant's nest. Eudasyphora on the other hand breed in cow dung and decaying material (Skidmore, 1991) so may have had early stages in the nest. Many gout flies (Chloropidae) also hibernate in winter, sometimes in large aggregations, so this may be the case with Siphunculina aenea rather than it having bred in the nest.
However, studies by Yamagishi, Okadome, & Ino (2003) in Japan have shown that some oriental species of Siphunculina breed in cormorant feces, so it would seem likely that S. aenea does too.
In early April spiders started to appear among the usual arthropod species. There was one Linyphiid species and several of the orb-web spider Larinioides cornutus, sometimes known as the 'furrow spider'. It is a species of reed beds and wetlands, often near the sea, so it is not surprising to see it from a cormorant's nest where, like
many of the other species, it will have overwintered.
Following this there was a quite period until mid-May with very few, or no, insects in the collecting bottle. I thought maybe we were not going to get very much more action but later on the month great quantities of a black fungus gnat (Sciaridae) started to emerge along with a Psychoda moth fly species and a lesser dung fly, Spelobia palmata.
There were several specimens of an interesting bark louse, Ectopsocus axillaris first described by Smithers in 1969. New (2005) writes "Initially reported from Ireland, this species has now been found in a yew tree in Edinburgh with additional records revealing that it is widespread in the Lothians, mainly on conifers by also on oak. It is now known also from Yorkshire. E. axillaris was described from New Zealand and subsequently discovered in Australia. Its origin remains uncertain, not least because its outdoor habits suggest that it may not be typically distributed in commerce as are many of the more 'conventional' psocids." It has also been recorded from Brighton and Hove. Marcus Oldfield, the Sussex recorder for Psocoptera, wrote in Adastra 2007: "I caught [E. axillaris] .... from a park mid-Hove and the other about 1 km from there in a copse in Brighton’s leafy suburbs. I suspect they’re probably a lot more around in Sussex, enjoying their anonymity, duly under-recorded. Strange, as this species, like many Psocids .... are unmistakable in the field and to the naked eye. Its wings are metallic, subtly reflecting a golden red/green sheen. No other Psocid I know has that distinction."
Today, 11 March 2009, there were fifteen Siphunculina and five of the common, overwintering Muscid fly Eudasyphora cyanella.
12 March 2009. Five Siphunculina aenea and one Anthomyiid (often difficult to identify to species level).
13 March 2009. Only one S. aenea today.
15 March 2009. A massive increase in numbers with over 100 Siphunculina aenea and eight muscid/calliphorids including Pollenia griseotomentosa and ? Phaona trimaculata.
17 March 2009. Again over 100 Siphunculina and half a dozen Calypterates.
18 March 2009. Today there were six E. cyanella, five P. griseotomentosa and only seven S. aenea.
19 March 2009. Much colder weather. Only 2 E. cyanella and 6 S. aenea.
23 March 2009. 40 S. aenea, 2 E. cyanella 1 ? Phaonia trimaculata.
24 March 2009. 3 S. aenea, 1 small Sciarid (black fungus gnat). The latter became very common after a few days.
5 April 2009 Over the last several days, S. aenea, E. cyanella and P. griseotomentosa have continued to appear. They have been joined by a regularly appearing black fungus gnat (Sciaridae) and I have one example each of a Psocid and a thrips. All these will be difficult to identify.
8 April 2009 One of the spiders has been identified as Larinioides cornutus.
12 April 2009 Two new species today among the more familiar things: Anthomyia procellaris and Parapiophila vulgaris. The latter, though usually a carrion feeder, has been bred from birds' nests (Stubbs & Chandler, 2001).
16 April 2009 E. cyanella, S. aenea and A. procellaris continue to appear in twos and threes every day but the Sciarids are now less common.
19 April 2009 Despite the fact that weather is slowly getting warmer, emergences seem tp be falling. Over the last few days we have had about eight Anthomyia procellaris and maybe a dozen Siphunculina. Today was the lowest number yet with only one S. aenea.
22 April 2009 Four A. procellaris, one S. aenea and two new species: the bug Anthocoris nemorum and a female Limnophyes non-biting midge.
2 May 2009 One Stygnocoris pedestris.
4 May 2009 One Ichneumon.
5 May 2009 There have been very few arrivals in the trap collecting bottle over the last 12 days but today there was a female non-biting midge (Diptera: Chironomidae). It was yellow with dark brown stripes and densely hairy wings but impossible to determine to more that Metriocnemus sp. Let's hope a male appears.
6 May 2009 One Anthomyia procellaris
7 May 2009 Spelobia palmata (several of these over the next few days). Small spiders continue to be common and tend to devour the smaller insects like Spelobia.
9 May 2009 Rather surprisingly one two-spot ladybird, Adalia bipunctata.
19 May 2009 Many Psychoda spp. have emerged in the last week or so. All one species I think and awaiting identification to species level. A surprise was one female of the tiny, subapterous bark fly Ectopsocus axillaris. This this was recorded a few years ago Brighton and Hove, but otherwise does not appear to be at all common in South East England. (For more details on this species see general text above). It has a black head and a distinctive metallic sheen. There was also a spider. On most days there seems to be a spider of one or another species but I don't think I have seen more than one at a time in the collecting bottle.
25May 2009 The number of insects in the collecting bottle continues to increase with the small sciarid, Spelobia palmata, and a Psychoda being the main species. There can be two or three hundred in the trap each evening now. One surprise today was the nettle ground bug, Heterogaster urticae. According to Southwood & Leston (1959) this nettle-feeding species hibernates "beneath bark or, frequently, within hollow woody stems in nearby plants." There are many such stems in the cormorant's nest.
26 May 2009 Another Heterogaster urticae among the hundred of so sciarids and smaller numbers of Psychoda.
27 May 2009 A very cold, wet day but the emergence of Sciarids continues unabated. There is also now the occasional apterous bark louse.
2 June 2009 Among the usual species there was today one Ectopsocus petersi a close relative of E. axillaris but without the dark head and bronzy sheen to the wins.
4 June 2009 Invertebrate numbers are lower again, but the usual species are present in small numbers and the fourth example of Heterogaster urticae turned up showing its presence is not accidental.
7 June 2009 A second example of Parapiophila vulgaris among the rather few species in the collecting bottle.
17 June 2009 Ectopsocus petersi and E.axillaris are the commonest species at present and the sciarids have virtually stopped. A surprise today was a male Metriocnemus albolineatus (Diptera: Chironomidae), a non-biting midge whose pupae have been recorded from the surface debris of pools and from moss on damp ground (Langton, 1991). It has also been bred from fungi and rotten wood and is probably widespread in East Sussex (Roper, 2005). The cormorants could easily have lifted material containing larvae or pupae to their nest.
6 July 2009 The last two or three weeks have been dominated by mass emergences of a small black fungus gnat (Sciaridae) which is most probably producing successive generations with the emergence trap. There are nearly always a few Ectopsocus axillaris and E. petersi among these as well as one or two Scatopse notata, a species not previously recorded. There have also been a couple of debris bugs, Lyctocoris campestris, a species of vegetable refuse including bird's nests (Southwood & Leston, 1959). This species sometimes sucks the blood of warm-blooded animals including man "their persistent attacks producing numerous small red spots".
31 August 2009 still a few Sciarids and one Lyctocoris campestris, but dozens of the springtail Entomobrya nivalis.
3 September 2009 A few species including Sylvicola cinctus and Graphopsocus cruciatus
6 September 2009 Several of the usual suspects and among them one new springtail: Orchesella cincta.
7 February 2010 The first records of 2010 after a brief mild spell - all springtails. There were four Entomobrya nivalis and one Isotomurus palustris, new for the nest.
9 February 2010 A very lively wood-boring weevil, Euophryum confine. An immigrant New Zealand species, first reported here in 1937, now widespread throughout Britain.
List of species to date
Sp. c (apterous)
Lyctocoris campestris Debris bug
Limnophyes sp. female (probably L. minimus)
? Phaonia trimaculata
Langton, P. H. (1991) A key to pupal exuviae of West Palaearctic Chironomidae. P. H. Langton, Huntingdon
New, T. R. (2005) Psocids Psocoptera (Booklice and barklice). 2nd edition. Handbooks for the Identification of British Insects, Volume 1, Part 7. Royal Entomological Society, London
Oldfield, Marcus (2008) New Psocoptera (book lice & bark flies) for Sussex in Adastra 2007. Sussex Biodiversity Record Centre, Woods Mill, Henfield.
Roper, Patrick (2005) Insects from an emergence trap over a small, dead oak trunk. British Journal of Entomology and Natural History 17: 212-216.
Skidmore, Peter (1991) Insects of the cow dung community. Occasional Publication No. 21, Field Studies Council, Preston Montford, Shropshire.
Southwood, T. R. E. & Leston, D. (1959) Land and Water Bugs of the British Isles. Frederick Warne, London.
Stubbs, Alan E. & Chandler, Peter J. (2001) A provisional key to British Piophilidae (Diptera) and Parapiophila flavipes (Zetterstedt, 1847) new to Britain. Dipterists Digest Volume 8. No 2.
Yamagishi, K., Okadome, T. & Ino, M. (2003) Biological notes on the flies emerging from the feces of great cormorant in Japan (Diptera). Medical Entomology and Zoology 54(3): 253-256 (Japan).