40.

SOME OF THE COMMON POND ARTHROPODA OF THE AUCKLAND DISTRICT

by Maureen H. Barclay.

CRUSTACEA

These form a class characterised by the presence of two pairs of atennae. Respirat• ion is accomplished by means of gills or directly through the body surface. Below is a classification of the main orders present locally: -

A. Subclass Branchiopoda - with many pairs of flattened thoracic limbs.

Order Cladocera (Water fleas). 4-6 pairs of thoracic appendages and a cara• pace over most of the body (all N. Z. species).

B. Subclass Ostracoda - Body entirely enclosed in a bivalve carapace.

Order Podocopa (Seed shrimps).

C. Subclass Copepoda - Body divided into a metasome (head and thorax) and a

urosome.

Order Eucopepoda

D. Subclass Malacostraca - Body of 20 segments, 5 head, 8 thoracic and 7

abdominal.

Order Amphipoda - Slater-like but body flattened from side to side.

Order Decapoda - Contains the fresh water crayfish. It must be realised that the keys listed for these orders do not by any means cover the total species list; only those examples which are more commonly encountered. CLADOCERA

In , only one superfamily is represented - the Chydoroidea, which is composed of 4 families, two of which are common locally.

Family Daphnidae. These have long, two-branched antennae, with three segments in

one branch and four in the other. The intestine has two diverticulae (hepatic caecae), at the anterior end. The following key intro• duces the main species: - l. (a) Shell markings mainly squares or rhomboids. Rostrum large. Genus Daphnia D. carinata King (Fig 1, la), is present in large numbers in ponds at Mangere. (b) Shell markings mainly oblique parallel lines. Small rostrum. Genus Simocephalus. 2.

2. (a) Head produced below to a rounded expansion. S. obtusatus Thomson (Fig 3). Collected frequently in ponds in the Dairy Flat-Silverdale area, (b) Head not as above. 3. 3. (a) Anal claw with a slight comb at the base. Ocellus rhomboidal. S. expinosus Koch (figs 2, 2a. ). The most common large pond cladoceran. Can also be collected from the edge of lakes and slow flowing streams, (b) Claw without comb. Ocellus elongated.

S. ventulus O. F. Muller (Fig 4, 4a). Not very common Has been collec• ted from a large farm pond at Papatoetoe.

Family Chydoridae. Small cladocera with both branches of the antennae three seg• mented. The rostrum is distinctly pointed.

1. (a) Body distinctly longer than high and flattened laterally 2. (b) Body more or less globular Genus Chydorus. See fig. 5.

C. sphaericus O F. Muller is perhaps the best known, occurring in small ponds, swamps and cattle troughs.

2 (a) Rostrum long and pointed. Pleuroxus hastirostris Sars (Fig 6, 6a). (b) Rostrum comparatively short and blunt. Alona guttata Sars (Fig 7, 7a)

Pleuroxus is a fairly common Chydorid, collected from most local ponds and lake edges. Alona has been found in a temporary pond at Ardmore.

OSTRACODA

These small, bivalved are quite commonly encountered in local ponds. At an average they are about 1-2 mm. long. At least 13 species can be found locally. The typical anatomy is shown in Fig. 8

The animals superficially fall into two main groups - the elongate, compressed non- swimmers, living in the bottom muds (see Fig 10), and the more rounded, active swimme (see Fig. 13). Identification of these animals unfortunately requires dissection of the appendages However below is an attempt to list some common species on external characters: -

Bottom dwellers:

Herpetocypris pascheri Brehm. A dark-green , with the dorsal edge of the valve slightly flattened (Fig. 9). This, together with Candonocypris is the most commc ly encountered bottom dweller. It can be found in most shallow, silty ponds and slow flowing streams

Candonocypris candonoides King. (Fig. 10, 10a) A paler green ostracod with a more rounded dorsal margin It is usually found in association with Herpetocypris except in running water, where it is usually absent.

Illyodromus spp. (Fig 11). These are a bright emerald green in colour, and usually have longitudinal striations on the valves.

Swimmers:

Cypretta sp. (Fig. 12). These are small, dark green animals, triangular when viewed

V3.

from above. They are found in varying numbers in practically every weedy pond in the area.

Cypris kaiapoiensis Chapman. (Fig. 13, 13a). A large, light green ostracod. In lateral view the greatest height is in front of the centre. This animal has been taken in large numbers from temporary ponds at Ardmore and Tamaki.

Eucypris sp. (Fig. 14, 14a) Rather like above but with the greatest height at about the centre and more compressed laterally. There are several small knobs present on the anterior edge of the valve.

Cypricercus sanguineus Chapman. (Fig. 15) A distinctively coloured red-brown animal with pale patches anteriorly and posteriorly Like Cypris it has been collected from temporary ponds.

Cyprinotus incongruens Ramdohr. (Fig 16) A common, cosmopolitan yellow ostracod usually found in small ponds and puddles devoid of much vegetation

These animals generally feed on decaying vegetation and are more often encountered in weedy ponds.

COPEPODA

There are three main suborders of - the Calanoida, Harpacticoida, and . Figure 17 shows the main differences in the external structure of these three

The Calanoids, with their elongate antennae, are mainly limnetic animals, living in the open waters of lakes. However Boeckella triarticulata is associated with the pond habitat and has been collected from a large farm pond at Papatoetoe.

The Harpacticoids are usually elongate bottom dwellers with poor swimming ability Movement is generally accomplished by a peculiar crawling or running They are not often encountered and the literature is sparse.

The Cyclopoids are the most common pond copepods and are all most monotonously alike. Most of the classification is based on the structure of the 5th leg - a small appendage situated on the genital segment. Acanthocyclops vernalis Fischer, is a fairly common, large , the fifth leg of which is shown in Fig. 18. This has been collected from most of the small ponds locally, and is present in large numbers in the temporary pond at Ardmore. Smaller species of Mesocyclops (Fig 19) and Paracyclops (Fig. 20) are also frequently met.

AMPHIPODA

These are more often associated with slow streams but large numbers of Paracalliope fluviatilis are present in the Western Springs lake.

DECAPODA

Here again, the "crayfish" species of Paranephrops (Fig. 21) are more commonly associated with streams and rivers. CRUSTACEA (^pepoda.

Cyclopoid Calanoid Harpacticoid

INSECTA. h5.

INSECTA

Insects possess a three segmented thorax typically with three pairs of legs. The head bears one pair of antennae and three pairs of mouthparts.

In many groups wings develop gradually throughout the life cycle, increasing in size at each moult. Here the young are designated as 'nymphs' and the orders and Hemiptera are included within this group. In the other orders the wings develop intern• ally and the early stages without wingpads are termed 'larvae' and the preadult instar with the wingpads as 'pupae1.

In only the aquatic beetles and bugs are both adults and nymphs or larvae adapted for living in the water.

Order ODONATA. Dragonflies and .

The nymphs of damselflies, or Zygoptera, are commonly encountered. They have a large labium which is folded under the head and shot out rapidly to entrap their prey. The abdomen is long and thin, terminating in three, leaf-like gills (see Fig. 22). The largest and perhaps most common larva is colensonis A slightly smaller, greenish tinged species is Xanthocnemis zelandica. The other type which may be collected is Ischnura aurora which has a speckled head and pointed anal gills See Fig. 23

Order HEMIPTERA. Bugs.

The water bugs are aquatic in all stages They have pointed, piercing mouthparts, usually in the form of a proboscis, which are used in feeding. Moving about on the sur• face film the squat Microvelia (Fig. 24) is commonly found. The other common surface dweller is the thin, elongate Hydrometra ribesci, although this is usually associated with the littoral vegetation rather than the actual water surface.

The two most active bugs within the water are representatives of the Notonectidae; Anisops assimilis - the well known 'backswimmer' and the Corixidae; arguta - the dorso-ventrally compressed 'water boatman' These two are rarely absent from the smaller lentic habitats.

Order TRICHOPTERA. Caddis flies.

The larvae and pupae only are aquatic. They usually construct tubes or cases in which to live The larval head has biting mouthparts, and the abdomen is usually with gills and a posterior pair of prolegs. Most caddis larvae in New Zealand are associated with streams but Triplectides cephalotes may be found in ponds, living in a case constructed of pieces of grass or twigs or even a hollowed out twig. The smaller Hydroptilids, Oxyethira (Fig 25) and Paroxyethira (Fig 26) with their transparent horny cases, are also sometimes encountered

Order COLEOPTERA. Beetles.

Most water beetles are aquatic in all stages of the life history, although sometimes 46.

the pupa may be buried in the mud above the water level. The best adapted are the fiercely carnivorous Dytiscidae. The dark brown Rhantus pulverosus (Fig 27, 27a) is one of the larger and more common examples Lancetes lanceolatum is about the same size and shape as Rhantus but has pale, longitudinal striations on the elytra. An Anti-porus larva with its peculiar cephalic projection is shown in Fig 28 The adult is about 5 mm long, dark brown with irregular lighter blotches. The smallest Dytiscid, about 2 mm long, is Bidessus plicatus, the larval head being pictured in Fig. 29-

Hydrophilid beetles, with their short, knobbed antennae, are easily distinguished from the Dytiscids by their clumsy movements in the water.

Order DIPTERA. Two-winged flies.

Certain families of flies have aquatic larvae, most of which are legless, and some of them are maggot-like They differ widely in their structure and the way they are adapted to live in water

The family Culicidae includes the mosquitoes, the larvae and pupae of which are well known. Culex pervigilans is perhaps the most commonly encountered. The Tendipedidae include the midges. The large red bloodworms of Chironomus zelandicus can often be found in the mud at the bottom of the ponds.

The Tipulid or cranefly larvae are stout and leathery and have a head partially retracted into the body At the posterior end is a spiracle-bearing disc surrounded by lobes. The larva is shown in Fig. 30.

Stratiomyid (soldierfly) larvae are located in shallow, weedy water These have reduced heads, no prolegs and a dorso-ventrally flattened body, pointed at both ends. See Fig. 31

The rat-tailed maggot larva of the Syrphid Tubifera tenax (Fig 32 ) is sometimes found in shallow, polluted ponds.

ARACHNIDA

Arachnids as a whole are characterised by the presence of four pairs of legs.

Order ACARINA. The mites.

The body of these animals is usually rounded and without subdivision, showing no sign of segmentation Most aquatic mites belong to the Hydracarina, with rounded or oval bodies and fairly good swimming ability The Hydrachnid mites found in Auck• land are, like most of their fellows attractively coloured in reds and browns They prey on the smaller crustacea, and worms and have an interesting life history, part of which is spent parasitically attached to the bugs Anisops and Sigara. The adults are 4 - 5'mm long.

Eylais sp. (Fig 33), is an attractive mite, coloured a bright red, slightly flattened dorsoventrally and has a characteristic swimming movement with the hind pair of legs trailing. Hydrachna sp. (Fig 34), is a spherical mite with the back strongly arched and brown- red in colour All the legs are used in swimming.

Arrenurus rotoensis Stout (1. 2 mm) This is a smaller, dark-brown mite, the body of which is flattened posteriorly.

Some much smaller mites, belonging to the Oribatidae, can sometimes be found clinging to vegetation or the surface film. These are not true water mites and are not capable of swimming (See Fig. 35). The group has not been worked on in New Zealand but local examples have been identified by Stout as belonging to the genus Hydrozetes.

Some useful references for the identification of Arthropoda:

Crustacea:

BREHM, V. 1929 Contributions to the knowledge of freshwater fauna of New Zealand Trans. N. Z Inst 59.

CHAPMAN, M. A 1963 A review of the fresh water of N. Z. Hydrobiologia 22(1): ppl-41.

HENRY, M. 1924 Entomostraca collected in the vicinity of Auckland, N. Z. Proc. Linn. Soc. N. S. W. 49: pp. 313-318. 48.

JOLLY, V. H. 1957. A review of the copepod genus Boeckella in N. Z. Trans Roy. Soc. N. Z. 84(4): pp. 855-65.

I960. Freshwater Cladocera in New Zealand. M Sc. Thesis (unpublished) Otago Univ

KEIFER, F. 1931. Report on a collection of freshwater Cyclopodia from New Zealand. Trans. N. Z Inst 62.

THOMSON, G. M. 1878. On the New Zealand Entomostraca. Trans. N. Z Inst. 11.

. 1882. On the New Zealand Copepoda. Trans. N. Z. Inst. 15, p. °»3

WARD h. WHIPPLE 1959. Chapters on Cladocera, Ostracoda and Copepoda. John Wiley, New York Publ.

Insecta:

FRASER, F. C. I960 A handbook of the Dragonflies of Australasia Roy. Zoo. Soc N. S. W. Publcn.

GRAHAM, D. H. 1930 Mosquitoes of the Auckland district. Trans. Proc. N. Z. Inst 60: pp. 205-244.

HUDSON, G. V. 1934 New Zealand Beetles. Ferguson & Osborn, Publishers.

MYERS, J. G. 1926. Biological notes on New Zealand Heteroptera Trans. N. Z. Inst 56: pp. 449-510.

PENNAK, R. W. 1953. Freshwater Invertebrates of the United States Ronald, New York

WISE, K. A. J. 1961. Larvae of three aquatic Beetles (Coleoptera: Dytiscidae) The N. Z. Entomologist. 2(6): ppl 8-22

YOUNG, E. C. 1962. The Corixidae and Notonectidae (Hemiptera-Heteroptera) of N. Z. Records of the Canterbury Museum 7 (5): pp. 327-374.

Arachnida:

STOUT, V. M. 1953 Eylais waikawae (Hydracarina) and some features of its life history and anatomy. Trans Roy. Soc. N. Z 81: 389-416.

1953. New species of Hydracarina with a description of the life history of two. Trans. Roy. Soc. N. Z. 81: 417-466.