Interspecific copulation in and co-occurrence of similar-sized freshwater centropagid copepods

1984 ◽  
Vol 35 (2) ◽  
pp. 153 ◽  
Author(s):  
EJ Maly

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.

2018 ◽  
Vol 10 (3) ◽  
pp. 1457-1471 ◽  
Author(s):  
Astrid Cornils ◽  
Rainer Sieger ◽  
Elke Mizdalski ◽  
Stefanie Schumacher ◽  
Hannes Grobe ◽  
...  

Abstract. This data collection originates from the efforts of Sigrid Schnack-Schiel (1946–2016), a zooplankton ecologist with great expertise in life cycle strategies of Antarctic calanoid copepods, who also investigated zooplankton communities in tropical and subtropical marine environments. Here, we present 33 data sets with abundances of planktonic copepods from 20 expeditions to the Southern Ocean (Weddell Sea, Scotia Sea, Amundsen Sea, Bellingshausen Sea, Antarctic Peninsula), one expedition to the Magellan region, one latitudinal transect in the eastern Atlantic Ocean, one expedition to the Great Meteor Bank, and one expedition to the northern Red Sea and Gulf of Aqaba as part of her scientific legacy. A total of 349 stations from 1980 to 2005 were archived. During most expeditions depth-stratified samples were taken with a Hydrobios multinet with five or nine nets, thus allowing inter-comparability between the different expeditions. A Nansen or a Bongo net was deployed only during four cruises. Maximum sampling depth varied greatly among stations due to different bottom depths. However, during 11 cruises to the Southern Ocean the maximum sampling depth was restricted to 1000 m, even at locations with greater bottom depths. In the eastern Atlantic Ocean (PS63) sampling depth was restricted to the upper 300 m. All data are now freely available at PANGAEA via the persistent identifier https://doi.org/10.1594/PANGAEA.884619.Abundance and distribution data for 284 calanoid copepod species and 28 taxa of other copepod orders are provided. For selected species the abundance distribution at all stations was explored, revealing for example that species within a genus may have contrasting distribution patterns (Ctenocalanus, Stephos). In combination with the corresponding metadata (sampling data and time, latitude, longitude, bottom depth, sampling depth interval) the analysis of the data sets may add to a better understanding how the environment (currents, temperature, depths, season) interacts with copepod abundance, distribution and diversity. For each calanoid copepod species, females, males and copepodites were counted separately, providing a unique resource for biodiversity and modelling studies. For selected species the five copepodite stages were also counted separately, thus also allowing the data to be used to study life cycle strategies of abundant or key species.


Behaviour ◽  
1993 ◽  
Vol 124 (1-2) ◽  
pp. 45-56 ◽  
Author(s):  
Steven R. Telford ◽  
J. Mark Dangerfield

AbstractField and laboratory observations of mating behaviour in a population of the tropical millipede Alloporus uncinatus were carried out over one breeding season. Males obtained mates through random encounters and by forming triplet associations with copula pairs. The occurrence of triplet associations in the field was coincident with a highly male biased operational sex ratio. Mate acquisition by males was apparently stochastic and direct physical competition did not occur. In laboratory experiments mating was size-selective probably as a consequence of female choice. We consider the possibility that sperm competition has contributed to the evolution of the mating system in this species.


1976 ◽  
Vol 54 (6) ◽  
pp. 933-940 ◽  
Author(s):  
Edward J. Maly

Two high-altitude copepods, Diaptomus shoshone and D. coloradensis, exhibit temporal differences in development and abundance, and they are of different size. Studies of adult sizes attained and of diets reveal that competition for resources between the two species is slight; however, laboratory experiments demonstrate that D. shoshone, the larger of the two species, preys extensively upon D. coloradensis. The population characteristics of the two species can be attributed both to avoidance of predation by the smaller species and to high variation in season length. Results are discussed in relation to theory, indicating that competition is a primary determinant of degree of resource overlap between congeneric species.


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