freshwater invertebrate recorder’s annual report

7 AQUATIC INVERTEBRATE REPORT

Trans. Suffolk Nat. Soc. 50 (2014)

FRESHWATER INVERTEBRATE RECORDER’S ANNUAL REPORT ADRIAN CHALKLEY

Having used my report in Transactions 48 to review the Suffolk Cladocera, (Chalkley, 2012) and that of volume 49 for a survey of the Hen Reedbeds, (Chalkley, 2013) this report returns to a more traditional format. There follows then a review of the more interesting freshwater invertebrate records made between Summer 2012 and Summer 2014. Wherever a common name exists for a species it is given before the Latin.

Within the report are details of nine species; two Beetles and seven Caddisflies, new to the Suffolk list.

The Cladocera (Water Fleas) Following my review of Suffolk Waterfleas two years ago I was able, with the help of the BRC and colleagues in the Cladocera Interest Group, to publish a provisional Atlas for the British Isles. The maps may be viewed on line at www.cladocera.org.uk and will as time allows be followed by distribution maps for Suffolk. Below are just a few of the more notable species records made since my review.

The widespread but rarely found carnivorous species The Giant Eyed Waterflea, Polyphemus pediculus was found in the Soke Dyke at Oulton Marshes during 2013 and 2014 but not in similar habitats at nearby Carlton Marshes. Other unusual finds during 2013 were Daphnia curvirostris and The Crystal Waterflea, Sida crystallina also from Oulton Marshes; Graptoleberis testudinaria from Framlingham Mere; Pleuroxus uncinatus from Framlingham Mere and Hullbecks Reservoir at the Arger Fen reserve.

The freshwater invertebrate community at Hen Reedbeds was decimated by the inundation of salt water when the sea wall collapsed during the Tidal Surge of December 2013. It was interesting therefore to find that the Small-headed Water flea Simocephalus exspinosus survived in good numbers. During my survey there in 2012 the similar Simocephalus vetulus was also found, but during a return trip in June 2014 only S. exspinosus had survived. This should not be surprising however, records from Stuart Warrington of the National Trust, show that the species is to be found on Orford Ness where all pools are within reach of sea spray, probably the most Easterly location in the UK for this species.

The Coleoptera (Water Beetles) I first visited Oulton Marshes (Plate 6) back in 2012 to look at some new turf ponds which had been created and I have been carrying out a long term survey there for the SWT which will finish at the end of this year. Of the more interesting beetles found there the most surprising to me was the discovery of several specimens of Hydaticus transversalis (Plate 7) in the more open dykes across the Marshes. This diving beetle is associated with rich fen in lowland ponds and ditches. It was recently rediscovered in the Cambridgeshire Fens and the Oulton specimens are a new county record for Suffolk. The only other species of Hydaticus, the slightly larger and more common Hydaticus seminiger, is also common at Oulton and frequently they


Suffolk Natural History, Vol. 50 8

were found together. In September 2013 I found Rhantus grapii in two of Oulton’s ditches. With a distribution following old remnant fenlands the last county record I have was from Lopham Fen in 2004 by Geoff Nobes.

Oulton Marshes also provided only the 6th record for Haliplus variegatus on my county database. First noted by Claude Morley somewhere in Ipswich in 1894 the only other records we have are from Redgrave in the 1960’s, Minsmere in 2003 and Lopham Fen in 2004. This is a nationally uncommon species of stagnant fens and is associated with stoneworts, Chara sp., its food plants. Other Haliplidae from Oulton were Haliplus immaculatus for which I have only seven other records this century; and Haliplus obliquus which, with nine other records on my database, was also a welcome find. In common with H. variegatus discussed above H. obliquus is associated with base rich habitats supporting stoneworts, which have quickly established in newly dug ponds at Oulton. Some 45 miles to the South West at Grove Farm, Norton stoneworts are also a noticeable feature in the new ponds and H. obliquus was also recorded there in both 2013 & 2014 by Rob Parker’s U3A group of aquatic recorders supported by an SNS bursary. Tostock Ley Pond at Grove Farm also provided the only record of Haliplus sibiricus in the last ten years, found by Rob Parker in August 2013.

Another species which is infrequently recorded in the county is Hydroglyphus geminus also found at Oulton Marshes in both August and September 2013. H. geminus was also recorded at Barn Meadow Pond, Grove Farm in May 2012 and Enochrus coarctatus was found there in May 2013.

The Artist Whirligig, Gyrinus urinator continues to pop up occasionally in the Rivers Box and Brett and was found at Homey Bridge in May 2014 by Jos Stone whilst on my Flatford Field Studies Centre identification course. During these courses the riffle beetles Brychius elevatus, Elmis aenea (Plate 8), Limnius volckmari and Nebrioporus elegans (Plate 9) are also regularly found in these two tributaries of the Stour. The very striking beetle N. elegans was also found for the first time in 2014 at Knettishall Heath following river restoration (see also below). Another whirligig only occasionally recorded in Suffolk is Gyrinus aeratus which was found at Carlton Marshes in July 2013 during a Field Studies Council training course on the invertebrates of Reedbeds.

The Great Silver Water Beetle, Hydrophilus piceus was found at Carlton during the same training day and the larvae was taken there during the SNS/SWT public recording day in July 2014. Other records of H. piceus during 2014 from near the coast were sent in by Jonathon Forsythe at Boyton Marshes in June, and Raymond Watson had an adult turn up to his moth trap at Hollesley on the 31st March. Silver Water Beetles seem to have a mainly coastal distribution in the county but Deborah Key recorded one at Redgrave Fen in June 2014 during an A level pond survey.

During April 2013 I found a single specimen of Hydroporus discretus in Flowton Brook, near Elmsett. Previously found at other sites on the same brook in 2006 and 2010 these were the only other records I have since the turn of the century although there are five previous records going back to Morley’s record from Tostock in 1911. In June 2013 I found what I thought was a small, brightly marked specimen of Suphrodytes dorsalis. However,



recent DNA analysis of Dytiscidae (Foster & Friday, 2011) has shown that there are two species that were previously represented by S. dorsalis. My specimen was in fact Suphrodytes figuratus; although it was my first record of this species I have since discovered that it was found in 2010 by Juliet Hawkins in Raydon Wood. I have yet to re-examine previous specimens of S. dorsalis which are highly likely to contain some earlier examples of S. figuratus but this is another new species to add to the county list. Another less common beetle found by Juliet during her farm pond surveys at Theberton in 2012 was Helophorus obscurus, which despite the whole beetle being only around 4 mm long needs to have the male genitalia dissected and measured under the microscope for certain identification.

In November 2012 some 20 new shallow pools were dug on Great Fen at the Redgrave reserve of Suffolk Wildlife Trust to provide possible future habitat expansion for the Fen Raft Spider, Dolomedes plantarius. During the summer of 2013 I was invited by Kerry Vaughan, the site manager, to survey the developing pools. Redgrave is known for interesting beetles and as usual it did not disappoint. The more interesting species I found are listed below. By the way I saw no Fen Raft Spider whilst at Redgrave and it seems at the moment that the best place to regularly see these impressive creatures is at the Carlton Marshes reserve where the introduced spiderlings have grown into successfully breeding adults and are relatively easy to see.

Beetles from Great Fen, Redgrave To put them into context the number in brackets shows the number of records for each on the county database since 2000.

Cymbiodyta marginellus (13) Dryops anglicanus (7) Dryops ernesti (2) Dytiscus semisulcatus (1) Enochrus coarctatus (13) Enochrus nigritus (5) Helophorus longitarsis (1) Hydaticus seminiger (17) Hydrochus angustatus (0 but 3 records pre 1910) Hydrochus crenatus (3) Hydrochus elongatus (13) Limnebius aluta (13) Liopterus haemorrhoidalis (19) Paracymus scutellaris (2) Rhantus grapii (12) Scarodytes halensis (1)

The Ephemeroptera (Mayflies) As discussed in my previous reports the rare mayfly The Scarce Purple Dun, Paraleptophlebia werneri at Elmsett continues to be the only population discovered in Suffolk and the only one known in Eastern Britain. I carry out regular monitoring of this population in spring just before hatching. I am



pleased to report that numbers were high in both 2013 and 2014 with larvae occurring over a 3∙5 km stretch of the watercourse. In the stream P. werneri occurs alongside two other species; the very common Large Dark Olive, Baetis rhodani and The Ditch Dun, Habrophlebia fusca which is fairly common in several headwater streams across the county.

In 2013 the SNS held a public ‘Taster Day’ at Knettishall Heath Country Park. The year before the first of a number of river restoration projects had been carried out there on the Little Ouse River. Previously the river had been slow flowing and a suitable habitat for only a limited number of mayfly species. By creating a more meandering flow across raised stretches of gravel extracted from the bed a number of faster riffle areas have been created. During the SNS recording day in 2013; The Medium Olive, Baetis vernus, The Anglers’ Curse, Caenis horaria, The Small Spurwing, Centroptilum luteolum, The Large Spurwing, Procloeon pennulatum, were identified along with Baetis rhodani. During a short visit with representatives of Anglia Water in 2014 I was able to add The Green Drake, Ephemera Danica and The Blue Winged Olive, Serratella ignita to bring the list of species to seven. Unfortunately I was unable to survey the river before the restoration, but it will be interesting to see how the Little Ouse responds to the ongoing work being carried out elsewhere along its course, including the installation of woody debris. The long term stability of these habitat modifications are, I feel, a little less certain without wider catchment improvements but in the short term the benefits seem clear.

The Heteroptera (Water Bugs) In Transactions 47 (Chalkley, 2010a) I described the discovery in August 2010 of a large colony of the Spined Pondskater, Aquarius paludum at Bixley Decoy lakes. This was the first county record of this large and distinctive species and it was expected that it would be discovered fairly quickly elsewhere in the county. However, despite an article in White Admiral (Chalkley, 2010b) no further sightings were reported until August 2012 when Trevor Goodfellow sent me photos of a flotilla of several hundred on a farm lake at Thurston. Like the first colony at Bixley this second one seems to have been there for some time and has continued to do well with large numbers recorded again by Trevor in 2013 and 2014. Then in September 2014 I found a single specimen of A. paludum on one of the newly constructed Turf Ponds at Oulton Marshes reserve. Thus we have three known sites within the county, although this last is unusual in that no large colony has been discovered nearby. I would welcome any information on sightings of any larger than normal pondskaters which have noticeable projections at the end of the abdomen.

Back in 2001 another aquatic bug, Sigara iactans was discovered at Framlingham Mere. This was probably the first record in Britain of the species which had spread from the continent. It was then discovered in the Centre Parcs Lakes at Elveden, where it has continued to do well and was found in good numbers when surveyed in 2013. In October 2013 I made a return trip to Framlingham Mere, where after twelve years a large population of S. iactans still survives. In the same year at Oulton Marshes S. iactans was



found in two of the new turf ponds. It seems that both of these recent additions to the aquatic bug fauna of the county have established themselves in breeding colonies in just a few sites which are unusually widely separated.

When surveying new spider pools at Redgrave in August 2013 a number of aquatic bugs where found. This included three out of the four species of Corixa, namely Corixa dentipes, C. panzeri, and C. punctata. These are the bigger of the many species of Lesser Water Boatmen, the other species Corixa affinis appears to be very rare in Suffolk and is infrequently seen. Amongst the smaller species of Lesser Water Boatmen found at Great Fen were Hesperocorixa linnaei, H. moesta and H. sahlbergi. Again this unusually comprises all the species on the Suffolk list in one site; one further species H. castanea occurs in the British Isles but I have only found this in Wales.

Another species taken at Redgrave was Notonecta viridis, a Backswimmer or Water Boatman which only comprises about a tenth of the backswimmer records we have. Notonecta glauca is by far the most common of the four species in the British Isles and this was also at Redgrave but N. maculata, our other Suffolk species, was not. I have put a photographic identification guide to the species of larger aquatic bugs on the SNS website www.sns.org.uk/pages/downloads.shtml to download. These are common bugs which can be found both in the countryside and many garden ponds, I would welcome more records especially via the iRecord website.

The Plecoptera (Stoneflies) There seem to be relatively few species of stoneflies in Suffolk, unsurprising as many are insects of mountains or at least of faster flowing and purer waters than currently exist in our county. At times they also seem to survive as relatively small populations. This seems to be the case in Hol Brook, a small stream not a kilometre from my house which feeds a lake and then flows through my own garden to the river Box. This year I found larvae of Pictet’s Small Brown Stonefly, Nemurella picteti in the lake inflow. I have recorded this species elsewhere in the Stour river system but was surprised to find it so near to home in what I considered to be an unfavourable habitat. This headwater of the Box suffers from considerable siltation, low flow rates and the lake itself has a very large population of roach, carp and stickleback. However the discovery, far from other known populations, showed me that Nemurella picteti is capable of surviving in small populations when conditions are less favourable. Perhaps it also tells me that I should have done more sampling closer to home in previous seasons instead of venturing to better sounding sites across the county! Ah well the water is always clearer in the next valley I suppose.

Of 33 species of stonefly in the British Isles only the nine listed below have been recorded in Suffolk and only five of those since the year 2000. Generally these records are from the headwaters and smaller streams in the county, and the four species with two or less records from the 20th century should be regarded as unconfirmed.



The Trichoptera (Caddisflies) Generally, in my annual report, I report on caddis larval records, since larvae are often caught during routine sampling whereas adults need searching for in bankside vegetation unless they are encountered whilst in flight, usually during swarming for mating. However, during Autumn 2012 and through 2013 Barry Wentworth and John Everson sent me adults caught during their moth trapping at Hen Reedbeds. This gave me samples for a whole season. In addition Raymond Watson also identified the adult caddis that were attracted to his moth trap, mostly from his garden in Hollesley

The following table summarises these adult caddis records showing the month they were in flight. All records are from 2013 unless otherwise stated. All records not from Hen Reedbeds were made by Raymond Watson. I would be pleased to receive further records or specimens from moth trappers.

Amphinemura standfussi Standfuss’ Small Brown 1 record 1989 Brachyptera risi Common February Red 2 records 1988 & 1993 Leuctra fusca Late Needle Fly 2 records in 2010 Leuctra nigra Black Needle fly 10 records 1990-1998 Nemoura avicularis Small Brown 8 records 1990 to 2006 Nemoura cambrica Small Spring Brown 4 records 1987 to 2000 Nemoura cinerea Small Dull Brown 2 records 1987 & 2007 Nemoura erratica Erratic Small Brown 1 record 1989 Nemurella picteti Pictet’s Small Brown 12 records 1961 to 2014

Species Records from

Family – Hydropsychidae The Marbelled Sedge Hydropsyche siltalai

Hollesley July & Aug

Family – Hydroptilidae Agraylea multipunctata Hollesley Sept Agraylea sexmaculata Hollesley Jul & Sept Oxyethira flavicornis Hollesley May June July Aug Sept Oxyethira simplex Hollesley Marshes Aug

Family – Lepidostomatidae

Crunoecia irroratus Hollesley July

Family – Leptoceridae Athripsodes aterrimus Hollesley July & Aug Ceraclea dissimilis Somerleyton June Ceraclea nigronervosa Hollesley July Ceraclea senilis Somerleyton June Leptocerus lusitanicus Hollesley Aug;

Bawdsey Hall Aug

Leptocerus tineiformis Hollesley July & Aug




Family – Leptoceridae cont.. The Grouse Wing Mystacides longicornis

Hollesley May June July Aug Sept & Oct; Hollesley Marshes June & July

Oecetis lacustris Hollesley Aug; Hollesley Marshes Aug

Oecetis ochracea Hollesley May June July Aug Sept & Oct; Hollesley Marshes Aug

Family – Limnephilidae The Mottled Sedge Glyphotaelius pellucidus

Hen Reedbeds Oct; Hollesley May, June Aug & Sept; Hollesley Marshes June July & Aug; Sizewell belts May; Somerleyton June

Grammotaulius nigropunctatus Hollesley June & Sept The Caperer Halesus radiatus

Hollesley Sept

Neureclepsis bimaculata Hollesley July Plectrocnemia conspersa Hollesley June;

Hollesley Marshes June & Aug; Somerleyton June

Limnephilus auricula Hollesley May June July Sept & Oct; Hollesley Marshes June & Aug; Sizewell belts May

Limnephilus binotatus Hen Reedbeds June & July; Hollesley May June & July: Hollesley Marshes June; Sizewell belts May, Somerleyton June

Limnephilus decipiens Hen Reedbeds Oct ‘12; Hollesley June July & Oct; Hollesley Marshes Aug

Limnephilus flavicornis Hen Reedbeds Oct ‘12; Jun, Oct & Sept ‘13 Hollesley July & Aug; Somerleyton June

Limnephilus griseus Hollesley May Limnephilus hirsutus Hen Reedbeds July The Cinnamon Sedge Limnephilus lunatus

Hen Reedbeds Oct ‘12 & Sept ‘13; Hollesley June July Aug Sept Oct & Nov; Hollesley Marshes June Aug Sept

Limnephilus luridus Hollesley Oct;




Family – Limnephilidae

The Cinnamon Sedge Limnephilus marmoratus

Hen Reedbeds June, Aug, Sept & Oct; Hollesley May June July Aug Sept & Oct ; Hollesley Marshes June July & Aug; Somerleyton June

Limnephilus rhombicus Hen Reedbeds June, July & Aug; Hollesley July

Limnephilus sparsus Hen Reedbeds June, July & Sept; Somerleyton June

Limnephilus vittatus Hollesley July; Grove Farm Oct:

Large Cinnamon Sedge Potamophylax latipennis

Hen Reedbeds Oct ‘12

Family – Phryganeidae Agrypnia pagetana Hollesley Aug & Sept ;

Hollesley Marshes Aug The Speckled Peter Agrypnia varia

Hollesley July & Aug; Hollesley Marshes July & Aug

The Murragh or Great Red Sedge Phryganea grandis

Hen Reedbeds June, July & Aug; Hollesley June & July; Hollesley Marshes June; Somerleyton June

Family – Polycentropodidae Cyrnus trimaculatus Hollesley Marshes Aug

Family – Limnephilidae

The Mottled Sedge Glyphotaelius pellucidus

Hen Reedbeds Oct; Hollesley May, June Aug & Sept; Hollesley Marshes June July & Aug; Sizewell belts May; Somerleyton June

Grammotaulius nigropunctatus Hollesley June & Sept The Caperer Halesus radiatus

Hollesley Sept

Neureclepsis bimaculata Hollesley July Plectrocnemia conspersa Hollesley June;

Hollesley Marshes June & Aug; Somerleyton June

Family – Psychomyiidae Lype reducta Hollesley Marshes Aug The Small Red Sedge Tinodes waeneri

Hollesley May & June



As I have said earlier the majority of caddis records on our database are for larvae, this is largely due to excellent keys for larvae having been available for many years, whereas good keys to adults where only produced recently, see my review in White Admiral 87 (Chalkley, 2014). There are no other records of the following species, listed in the table above, and may therefore be viewed as the first county records unless any reader can let us know otherwise. Agraylea sexmaculata**, Ceraclea dissimilis, Ceraclea senilis, Leptocerus lusitanicus, Limnephilus hirsutus, Oxyethira flavicornis, Oxyethira simplex

** In fact although Raymond’s record of the micro-caddis Agraylea sexmaculata may surely be viewed as a first county record literally the day after I wrote this I discovered two larval specimens in samples taken from Oulton Marshes during Autumn 2014. At under 4∙5 mm for the adult and less for the larvae I am sure the species is under recorded and light trapping for caddis will reveal more sites for this species.

There are also no larval records of the following species, although they were recorded by Claude Morley as adults and I have examined his pinned specimens which are still in the collections of the Ipswich Museum.

Crunoecia irroratus, 3 records the last in 1934; Limnephilus auricula, 11 records the last in 1938 Limnephilus luridus, 18 records the last in 1936; Grammotaulius nigropunctatus, 6 records the last in 1932

The Freshwater Triclads (Planarians or Flatworms) Of the twelve species of flatworm in the British Isles ten have been recorded in Suffolk, the two species of the genus Phagocata being absent. Some, like Polycelis nigra or P. tenuis and Dugesia lugubris or D. polychroa are present across the county. Some like Crenobia alpina occur infrequently where we have shaded, cool and especially spring fed streams. C. alpina was last found by Paul Lee in Braziers Wood Stream in September 2000. Also infrequent is our largest and most impressive species Bdellocephala punctata which Emma Royle found in May 2014 in the river Box, this was the first record since 2007.

Polycelis felina with 80 records on my county database is more frequent but nevertheless had only been found twice since the year 2000. Then in 2013 I found it twice; at the stream in Spouses Grove and in the Box at Homey Bridge. In April 2014 Rob Brown took it in the Hintlesham Watercourse and a month later I found it in the spring fed stream feeding the lake in Boxford where I found the stonefly, Nemurella picteti previously mentioned. Requiring somewhat the same habitats as C. alpina but more tolerant of greater flow and higher temperature P. felina is doubtless under recorded. However it may be easily looked for by simply turning over stones on the bed of small, especially spring fed streams. No special equipment is required and specimens do not need to be preserved for identification, indeed it is almost impossible to preserve flatworms in the normal way with alcohol or other fluids. Only 8–12 mm long and with pointed tentacles at either side of the head P. felina is easily recognised and there are plenty of



photos on the internet to check against. Just ensure you use a magnifying glass to check that it has numerous eyes along the front and sides of the head, the only other British flatworms in freshwater which may have tentacles, Crenobia alpina and Dugesia tigrina, have two large rather than multiple eyes though occasionally animals with one eye divided into two are found. Again more records of flatworms would be welcomed from amateur naturalists.

References Chalkley, A. K. (2010a). Freshwater Invertebrate Recorder’s Annual Report

2010/2011. Trans. Suffolk Nat. Soc. 47: 65–71. Chalkley, A. K. (2010b). Aquarius paludum, A new county record for Suffolk.

White Admiral. Suffolk Nat. Soc. 77: 6–7. Chalkley, A. K. (2012). Freshwater Invertebrate Recorder’s Annual Report

2012. Trans. Suffolk Nat. Soc. 48: 93–101. Chalkley, A. K. (2013). An Aquatic Invertebrate Survey of the Hen Reedbeds.

Trans. Suffolk Nat. Soc. 49: 53–72. Chalkley, A. K. (2014). Book Review: The Adult Trichoptera (caddisflies) of

Britain and Ireland. RES Handbooks 2012. White Admiral. Suffolk Nat. Soc. 87: 12–14.

Foster, G. N. & Friday, L. E. (2011). Keys to adults of the water beetles of Britain and Ireland (Part 1) (Coleoptera: Hydradephaga). Handbooks for the Identification of British Insects 4: 97–99.

Adrian Chalkley Freshwater Invertebrate Recorder 37 Brook Hall Road Boxford, Suffolk CO10 5HS Email: [email protected] Phone 01787210140 Twitter: @Box_valley



Plate 6: Drainage Dyke on Oulton Marshes SWT Reserve. (p. 7).

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Plate 7: Hydaticus transversalis, smaller than the great diving beetles but related to them this diving beetle is only 12 mm long. A rare invertebrate, with other modern records restricted to the Norfolk Broads, Cambridgeshire Fens and Somerset Levels. It is classified as Nationally scarce . (p. 7).

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Plate 9: Nebrioporus elegans A common riffle beetle, recorded for the first time at Knettishall in 2014 following the river restoration. Between 4 & 5 mm long and needing riffles - shallow stretches of stones over which the river ripples. (p. 8).

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Plate 8: Elmis aenea A common riffle beetle, in many headwater streams and small rivers. Only about 2 mm long and needing riffles - shallow stretches of stones over which the river ripples (p. 8).

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freshwater invertebrate recorder’s annual report

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