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Three species of Boeckella (B. triarticulata, B. dilatata and B. hamata) were reared from copepodite I to adult at three naturally fluctuating food levels and three temperatures in a 3 × 3 × 3 factorial design. Development times, lengths, times to produce the first clutch, clutch sizes, egg voumes, interclutch times, infertile clutches, total egg production, total reproductive time and mortality were measured. Development times for the three species were surprisingly similar but mortality differed among the treatments. The three species differed in their reproductive strategies. B. triarticulata, the largest species, produced a few large clutches. B. dilatata, the smallest species, produced many small clutches and invested the most energy per egg. B. hamata produced larger clutches than B. dilatata but not as many. B. hamata was the most tolerant of low, food levels and exhibited the most plasticity across the treatments. Thus, greater plasticity in life history characters is associated with survival in a wider-range of conditions.

Calanoid copepods belonging to four species and one subspecies from lakes and ponds mainly from the Cordillera Oriental (22) and Cordillera Central (1) of the Colombian Andes are recorded. Most of the water bodies studied are located in the ‘paramo’ region, between 2996 and 4085 m altitude. The family Boeckellidae is recorded for the first time from Colombia. Taxonomic characteristics of Boeckella occidentalis Marsh, 1906, Boeckella gracilis (Daday,1902) and the diaptomid Prionodiaptomus colombiensis (Thiebaud, 1914) are discussed. A new diaptomid genus, Colombodiaptomus, with one species and one subspecies are established.

SUMMARY. 1. The impact of parasitism by a fungus Aphanomyces sp. (Phycomycetes: Saprotegniaceae) on a population of Boeckella hamata in Lake Mahinerangi in New Zealand was studied over 20 months. The incidence of infection among adult female copepods exceeded 12% throughout winter (May-October) and was highest in autumn (46%) when population birth rates were depressed by 48.8%. During most of the study, parasitism lowered the rates of population recruitment and growth by more than 10%. These effects on the B. hamata population exceeded those of Aphanomyces on Boeckella dilatata Sars in another study. 2. It is hypothesized that the high incidence of parasitism by Aphanomyces and its importance at times in regulating populations of Boeckella in New Zealand lakes may be an ecological consequence of life in predator-poor ecosystems.

The rate of oxygen uptake by Boeckella dilatala collected from Lake Hayes was measured at four different temperatures using the micro‐Winkler technique. The rate of oxygen consumption increased with increasing temperature between 10°C and 20°c, and then declined. This is compared with the patterns shown by B. delicata, B. symmetrica and Calamoecia lucasi, and regression equations relating loge oxygen uptake, temperature, and loge dry weight for the four species are presented.

Seasonal variations in the species composition, abundance, biomass, and vertical distribution of zooplankton in two eutrophic, warm‐monomictic lakes are described for the period December 1969 to February 1972. In Lake Hayes, Boeckella dilatata was the dominant crustacean and Ceriodaphnia dubia was subdominant. Lake Johnson was dominated by Ceriodaphnia and Bosmina meridionalis and Boeckella were subdominant. Daphnia were common in spring in Lake Hayes, but very rare in Lake Johnson. Chydorus and Asplanchna appeared in summer in both lakes. Zooplankton were slightly more abundant in both lakes in 1971 than in 1970; the annual mean was 1.7 times higher in Lake Johnson than in Lake Hayes in both years. Biomass was highest in spring. In Lake Hayes it ranged from 0.7 to 4.6 g.m‐2 dry weight; in Lake Johnson it fluctuated in 1971 from 0.3 g.m‐2 in March to 7.4 g.m‐2 in November. Animals occurred at all depths during holomixis, but were nearer the surface during stratification. Vertical distribution was often bi...

Seasonal changes in species composition and abundance of zooplankton in Lake Taupo were measured at three sites each month from August 1974 to January 1976. The normalised data showed no differences in abundance between sites. Crustaceans comprised 50.3% and rotifers 49.7% of the zooplankton. Boeckella propinqua was the most prominent crustacean especially in spring and early summer, whereas the rotifers, dominated by Polyarthra vulgaris and Conochilus coenobasis, appeared in late summer, autumn, and winter.

Two calanoid copepod genera, Boeckella and Calamoecia have broadly similar geographic distributions in Australia but Boeckella is more common than Calamoecia. A field survey and literature search indicate that Boeckella is usually the first calanoid to colonize newly formed bodies of water, and Boeckella is more common in temporary pools and in high altitude environments. Boeckella usually produces larger clutches than Calamoecia, increasing its probability of establishment in lakes and ponds; calculations indicate that Boeckella's probability of establishment is far greater than that of Calamoecia. That Calamoecia is common on the North Island of New Zealand may be due to the presence of planktivorous fish; small species are more likely to survive in such environments. Calamoecia clutches may be able to move more often and farther than those of Boeckella but Calamoecia remains rare because its probability of establishment is low. Boeckella may be able to survive temporary pool environments not only because it can produce larger clutches, but also because many species in this genus are highly pigmented, and as such can survive brightly lighted environments. Patterns of abundance of North American diaptomids appear to be consistent with factors affecting those of Australian and New Zealand centropagids.

Aphanomyces ovidestruens, a fungus parasitic on the calanoid copepod Boeckella dilatata, is reported from two eutrophic lakes in New Zealand. Several differences between the parasite on B. dilatata and that described originally from Diaptomus gracilis were noted: the infection hyphae on B. dilatata did not swell distally into “bulbous appressoria” and the oogonia were typically larger and ornamented with spines or tubercles. The incidence of infection among adult female B. dilatata from 1969 to 1978 varied from nil to over 20% in both Lake Hayes and Lake Johnson and reached a peak of 47.7% in Lake Hayes in October 1977. Infection was highest in winter, spring, and late summer and lowest in early summer and autumn in both lakes. In Lake Hayes, peaks of infection roughly coincided with times when numbers of adult females of successive copepod generations were waning; this implies that the incidence of infection increases with female age after maturation.

The invertebrates and macroalgae in 42 permanent and temporary ponds and kettles in glacial moraine south of Lake Ohau, and 36 sites in moraine west of Lake Tekapo, South Island, New Zealand, were sampled in December 1980, and taxonomic lists were compiled. Most organisms belonged to taxa characteristically found in shallow waters elsewhere in New Zealand, but new distributions for the rare cladocerans Neothrix armata, Monospilus dispar, and Ephemeroporus barroisi were recorded, and the presence of Simocephalus acutirostratus in New Zealand was confirmed. Darkly pigmented Daphnia carinata were recorded for the first time as also were co‐occurring Boeckella triarticulata and Boeckella dilatata. Cluster analysis of the data from both areas identified 3 groups of taxa with a high probability of co‐occurrence. Some species were absent from all the sites in 1 area but present at several sites in the other. This may reflect differences in adaptation to drought, or the limited sampling regime, but is al...

Embryonic development times of Boeckella triarticulata, B. dilatata and B. hamata are compared. Two species, B. triarticulata and B. hamata had widely varying embryonic development times. Variable development times often resulted in greater hatching success.

Boeckella tanea, n.sp. is described. It shows similarities to B. propinqua and B. delicata, and appears to be confined to lakes and ponds in Northland, New Zealand.

In a study of four species of centropagid copepods, particularly Boeckella minuta Sars, occurring in south-east Queensland, Australia, body length was found to correlate with the rate of water renewal in the reservoir. Ravera & Tonolli's explanation for interpopulational differences in lengths of copepods has thus been confirmed. There was also a positive correlation between body length and egg number in ovigerous females. Sex ratio (females/males) increased with the rate of water renewal, this providing for relatively more females to be present when population numbers were smaller.

The Auxiliary Nihotupu Reservoir, near Auckland, New Zealand, was studied during 1967-68. The reservoir was emptied for a short time during the study. Changes in physico-chemical factors, phytoplankton and zooplankton were followed throughout the year. Thermal stratification was evident over the summer and the partitioning of oxygen and pH at this time is discussed. An acid heterograde pH curve is reported. From an analysis of oxygen deficits it is suggested that the reservoir may be oligotrophic. An analysis of egg production, length distributions and changes in developmental stages was used in interpreting the life cycle of Boeckella propinqua. Development times from egg to adult, and approximate survival rates are briefly considered. Mesocyclops leuckarti is also discussed and the annual cycles of both copepods are compared with those in other New Zealand lakes.

Summary Boeckella minuta is recorded from the Wellington water supply. Salient characteristics are described, and female and male fifth legs are figured.

The species composition, species abundance and size distribution of the zooplankton community of four farm dams in the Adelaide Hills were largely controlled by predation. In three farm dams without fish, winter-spring zooplankton communities were dominated by the large cladoceran Daphnia carinata and a species of the large calanoid Boeckella along with smaller populations of Calamoecia, Ceriodaphnia, Mesocyclops leuckarti and Asplanchna brightwelli. The mean length of zooplankters in each of the dams was 0·95, 1·28 and 1·33 mm, and the largest zooplankters were 3·6 mm. In summer, large populations of the notonectid Anisops deanei decimated the zooplankton and virtually eliminated D. carinata. Mean length of zooplankters in each dam was 0·60, 0·81 and 0·83 mm, and no specimens were more than 1·60 mm. In the dam heavily stocked with redfm (Perca fluviatilis), the zooplankton community was dominated by Tropocyclops sp., Mesocyclops leuckarti, Bosmina meridionalis, Ceriodaphnia spp., Brachionus spp. and Asplanchna spp. D. carinata and calanoids were absent. Mean and maximum sizes of zooplankters were 0·50 and 0·83 mm in winter and 0·37 and 0·80 mm in summer. The roles of dispersal, competition and predation in determining community structure are discussed. Consideration is given to how the type and extent of predation and the environmental conditions might affect the importance of predation in other farm dam or pond systems.

Laboratory experiments were performed in which males of a given centropagid calanoid copepod species were placed with females of another species. Five interspecific pairings were tested, and in four of these, males attempted copulation or copulated with the partner of a different species. Metasome lengths of copepods in all populations used for experiments were determined: males attempted copulation with females whose average length was 0.88-1.09 times the normal size of the female for that species. These results imply that co-occurrence of similar-sized calanoids may be rare because of mating behaviour, temporal or spatial differences in mating, rather than because of competition for resources. A survey of reported co-occurrences of centropagid copepods in the genera Boeckella and Calamoecia found in Australia supports this contention.

Sediment cores from two lakes on the Antarctic Peninsula, Hidden Lake on James Ross Island and Lake Boeckella in Hope Bay, are described, analysed and dated with regard to climatic changes during the Holocene. It was found that lichenometry, using Rhizocarpon geograficum, can be used locally to separate moraines of different age. Minimum datings of the deglaciation were found to be 8680 B. P. in Hope Bay and 3900 B. P. in the Hidden Lake area. A cold period, culminating around 5000 B. P., can be dated in the sediment from Lake Boeckella. A slightly lower content of organic material in the lakes around 2100 B. P. might be caused by a slightly colder climate at that time. Evidence of a very distinct climatic deterioration around 800 B. P. can be found in the sediment from Hidden Lake. Weaker traces of a colder climate can be found in Lake Boeckella around 500 B. P.

Fifty-three temporary freshwater pools (mean depth 23 cm) located mainly in eastern Victoria were studied from February to September 1973. Chemical parameters determined were pH (range 5.7-8.2, mean 6.9), conductivity (K18, range 55-5500, mean 340 �S/cm), dissolved oxygen (range 23-170, mean 72% saturation) and turbidity (range 2-310, mean 50 Formazin turbidity units). A total of 60 microcrustacean species was recorded. The Australasian endemic cladoceran, Saycia cooki (King), was of common occurrence from June through to August. The fact that it tends to reach peak numbers early in the life of a pool is probably related to the production of large numbers of ephippial eggs. In contrast, cladocera which produce only one or two ephippial eggs, such as Chydorus, Moina and Simocephalus, tend to appear later in succession. Simocephalus expinosus (benthic) and Daphnia carinata, s.l. (planktonic) had mutually exclusive distributions and are apparently unable to coexist in shallow waters. Endemic cyclopoid copepods encountered included three new species of Microcyclops, M. arnaudi (Sars), Acanthocyclops australis Sars, and Acanthocyclops, sp. nov. Like Saycia, Microcyclops varicans and Acanthocyclops bisetosus exhibited maximal numbers early in succession. Several new combinations of coexisting calanoid copepod species belonging to the genera Boeckella and Hemiboeckella are reported. Computer analysis showed that the following four groups of species had a high probability of co-occurrence: (1) Cypretta sp., Attheyella australica, Ilyodromus sp., Saycia cooki; (2) Cyprinotus leanus, Acanthocyclops bisetosus, Moina tenuicornis; (3) Boeckella major, B. pseudochelae, Cypris sp., Daphnia carinata, s.l. ; (4) Simocephalus exspinosus, Microcyclops varicans.

The freshwater calanoid copepods Boeckella triarticulata and B. hamata were found in ponds near Napier. These are the first records of B. triarticulata in the North Island, New Zealand and of B. hamata in the east coast, North Island.

The zooplankton of Lake Cootapatamba, the highest (2070 m) alpine cirque lake in continental Australia, was sampled monthly during the ice-free periods of 1981 and 1982. Eleven taxa were identified, the zooplankton being dominated by Boeckella montana, B, pseudochelae, Daphnia nivalis, and in one month, Keratella slacki. Partial correlations with physicochemical parameters (pH, conductivity, O2 and temperature) indicated no strong and consistent trends with zooplankton numbers. In addition to possible competitive effects between K. slacki and the crustaceans (marked by strong spatial and temporal segregation), circumstantial evidence is produced for a direct control by food on the major population changes in 1981 and 1982.

Two new species, Hemiboeckella powellensis and Calarnoecia elongata, and a new subspecies, C. gibbosa newmannensis, are described from Western Australia. Boeckella orientalis Sars from Mongolia is placed in synonymy with B. triarticulata (Thomson) from Australasia. B. saycei Sars is removed from synonymy with B. propinqua Sars and detailed instructions for the discrimination of these two species are given. Further information is supplied for B. nyoraensis Searle, B. opaqua Fairbridge, B. bispinosa Bayly and the C. tasrnanica complex. Species of Boeckella that are restricted to, or characteristic of, temporary waters tend to have a higher mean number of eggs per clutch than do the perennial species of permanent waters. Addition- ally the number of eggs in each clutch may be less variable in temporary-water species than in those that are perennial. A comprehensive list of the Australasian species of the three genera is provided, and a summary of their distribution is given.

A study was made of the zooplankton of a small, warm monomictic, closed, alkaline lake. This was located on Mayor Island, an offshore island of the North Island of New Zealand. Morphometric, thermometric, and chemical aspects of this lake are discussed. The vertical distribution of the zooplankton was investigated by the vertical hauling of a closing net and by the horizontal towing of a Clarke Bumpus sampler. The vertical distribution of zooplankton biomass and of the different planktonic crustacean species at different times of the year is discussed. When thermal stratification was well developed, all crustacean and rotatorian species had a very sharply defined lower limit between the upper limit of the metalimnion and the thermocline; minimal population densities existed some distance above this lower limit. A reversed diurnal vertical migration is reported for Daphnia carinata and the mature males of Boeckella propinqua. The following investigations and findings refer to Boeckella propinqua: the vertical distribution of four population components (CI-V, C VI male, male, C VI female, female , and C VI female, female, with eggs) at different times of the year is discussed; departure of sex ratio from 1 : 1 is reported; cyclic seasonal changes, which correlated inversely with temperature during part of the year, occurred in mean length and mean number of eggs in sacs; mean egg number also correlated with mean body length; considerable simultaneous interpopulational variation in mean egg number was found; length measurements of adults from November surface collections showed a bimodal distribution, and at the same time vertical variation occurred in the nature of size-frequency distributions-in both sexes the upper mode was progressively diminished with increasing depth and finally eliminated; in these November collections the percentage of lower modal females with eggs was much smaller than that for upper modal ones; when surface collections showed unimodal size distributions there appeared to be no vertical variation in size-frequency distributions; variation in the lobulation of the last metasomal segment of females is mentioned; the occurrence of a cestode cysticercoid stage in male and female stages CV and VI, and parasitic castration of C VI male, male, is reported. General observations are made on the Rotatoria and the vertical distribution of Filinia longiseta is dealt with. Comparisons are made between the zooplankton of a number of mainland lakes and that of the Mayor Island lake.

The taxonomic utility of various characters is discussed. The status of Hemiboeckella searli Sars is discussed, and the retention of the monotypic genus Hemiboeckella is considered to be justified. A list of generic characters is given for both Boeckella and Hemiboeckella, a key is given to the Australasian species of Boeckella and is accompanied by comparative drawings. Except for B. minuta Sars, this key does not enable female specimens to be identified. The number of Australasian species of Boeckella previously described is reduced from 25 to 14 by synonymy. Two new species, B. geniculata and B. montana, and a new subspecies, B. robusta maxima, are described. Another apparently new species is figured but not named (based on a single specimen only). Two species described from New Zealand are recorded from Australia for the first time. The male fifth legs of all species are described and, except for B. opaqua Fairbridge, all are figured. Additional features are also figured for some species. The distribution of species and some general aspects of their ecology are discussed.

Isias uncipes sp. nov. described here is the first representative of the genus to be recorded from the southern hemisphere. Comparison is made of structural features of Centropages, Isias clavipes, I. uncipes, Gladioferens, Boeckella, Hemiboeckella, and Calamoecia. The phylogeny of the Centropagidae is discussed.

The species Diaptomus (Eodiaptomus) lumholtzi Sars and D. (Tropodiaptomus) australis (Kiefer) are redescribed and figured. Both species are recorded from numerous new localities in northern Australia. The southern limit of distribution of D. lumholtzi is discussed in relation to the northern limit of Boeckella. A single example of the coexistence of D. lumholtzi with Boeckella triarticulata, and three examples of coexistence of D. lumholtzi with Calamoecia are cited.

Eleven lakes were examined in varying degrees of intensity. For the largest two, Lakes Elusive and Barracoota, information is presented on physiography, major physical and chemical features, macrophytes, zooplankton, littoral invertebrates, benthos, and fish. Limited data, mainly on water chemistry and zooplankton, are given for the remaining lakes. The lakes are divisible into three groups. The four floodplain lagoons contain alkaline water dominated by sodium and bicarbonate ions. Zooplankton in each consists of Boeckella minuta, Thermocyclops hyalinus, and Daphnia lumholtzi, as well as a variety of other entomostracans. The coastal dune lakes have acid water dominated by sodium and chloride ions and a restricted zooplankton of one to three species, including Calarnoecia tasmanica. Compared with coastal dune lakes of southern Queensland, these are heterogenous in mode of origin, water chemistry, and zooplankton. Despite some similarities with dune lakes, Lake Barracoota is basically different. Its physiography suggests a recent marine origin which is confirmed by the presence of two isopods and a polychaete with marine affinities.