Instar Succession, Vertical Distribution, and Interspecific Competition Among Four Species of Chaoborus

1977 ◽  
Vol 34 (1) ◽  
pp. 113-118 ◽  
Author(s):  
John C. H. Carter ◽  
Judith K. Kwik
Keyword(s):  
Life Cycle ◽  
Vertical Distribution ◽  
Interspecific Competition ◽  
River System ◽  
Spatial Separation ◽  
Oligotrophic Lakes ◽  
Intense Competition ◽  
Chaoborus Punctipennis ◽  
Competition For Food

Of four highly oligotrophic lakes of the Matamek River System, Quebec, Lac à la Croix contains Chaoborus punctipennis and C. trivittatus, Lac Gallienne C. americanus, Lac Randin C. americanus and C. trivittatus, and Lac Méchant C. flavicans and C. trivittatus. The instars are all planktonic except instars I–III of C. trivittatus in Lac à la Croix. All species have a 1-yr life cycle except C. americanus in Lac Gallienne which has a 2-yr cycle. The cycles of C. trivittatus in lacs Randin and Méchant are out of phase by 1 mo or more with those of C. americanus and C. flavicans, respectively. Seasonal increases in length occurred in most instars except those of C. punctipennis in Lac à la Croix. Both species in Lac à la Croix made fairly extensive diurnal migrations but in lacs Gallienne and Méchant all species remained near the surface. Intense competition for food is considered the most likely cause of seasonal or spatial separation of instars of similar size in all lakes.

Baetis zdenkae sp. nov., a new representative of the Baetis buceratus species-group (Ephemeroptera: Baetidae) from Rhodos (Greece) with notes to species-grouping of the subgenus Baetis Leach, 1815 s. str.

Zootaxa ◽  
2009 ◽  
Vol 1972 (1) ◽  
pp. 1-19 ◽  
Author(s):  
TOMÁŠ SOLDÁN ◽  
ROMAN J. GODUNKO
Keyword(s):  
New Species ◽  
Life Cycle ◽  
Vertical Distribution ◽  
Species Group ◽  
Basic Data ◽  
Male And Female ◽  
European Species ◽  
Species Groups ◽  
A New Species ◽  
Species Grouping

The male and female imago (subimago of both sexes unknown), and larva of a new species belonging to the Baetis buceratus species-group, namely Baetis (Baetis) zdenkae sp. nov. from Rhodos Island are described and illustrated in detail. Substantial diagnostic characters of males and larvae of the whole B. buceratus species-group are summarized and its position relative to other species groups is discussed. Critical characters distinguishing B. zdenkae sp. nov. from all other representatives of the B. buceratus species-group are emphasized and a discussion of 22 characters of the remaining 6 European species-groups of the subgenus Baetis Leach, 1815 s. str. and their relationships is offered. Available data on the biology of B. zdenkae sp. nov. (vertical distribution, habitat, current and substrate preference, abundance and density, possible life cycle type, and mating flight and oviposition patterns) and distribution with respect to possible endemism are given. Basic data on biology and area of distribution of Westpalaearctic species Baetis (Baetis) buceratus Eaton, 1870, B. (B.) nexus Navás, 1918 and B. (B.) spei Thomas & Dia, 1985 known only from Lebanon are summarized and compared to those of B. zdenkae sp. nov.

Effects of interspecific competition on food hoarding and pilferage in two sympatric rodents

Behaviour ◽  
2014 ◽  
Vol 151 (11) ◽  
pp. 1579-1596 ◽  
Author(s):  
Hongmao Zhang ◽  
Haiyang Gao ◽  
Zheng Yang ◽  
Zhenzhen Wang ◽  
Yang Luo ◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Sympatric Species ◽  
Rodent Species ◽  
Nocturnal Activity ◽  
Food Hoarding ◽  
Intense Competition ◽  
Apodemus Peninsulae ◽  
Chinese White ◽  
Field Mice ◽  
Competition For Resources

Food hoarding and pilferage in rodents may be regulated by intense competition between sympatric species that have similar habitats, diets and activity, but studies exploring this remain rare. Here, we used semi-natural enclosures to investigate food-hoarding and cache pilferage interactions between sympatric Korean field mice (KFM) (Apodemus peninsulae) and Chinese white-bellied rats (CWR) (Niviventer confucianus). KFM and CWR have similar diets, habitat and nocturnal activity, but the smaller KFM larder and scatter hoards and larger CWR larder hoard only. We found that KFM harvest, larder-hoard and eat seeds at a greater intensity when CWR are present as an audience (present but cannot pilfer). KFM ate 11.5%, re-larder-hoarded 17.9% and re-scatter-hoarded 1.3% of their scatter-hoarded seeds, and ate 29.3% of their larder-hoarded seeds when CWR were present as pilferers. A total of 12.8% of the seeds scatter-hoarded and 50% of seeds directly put on the ground by KFM were pilfered by CWR. CWR did not alter hoarding intensity in the presence of KFM and their stores cannot be pilfered by KFM. These results indicate that large-sized rodent species (more dominant) significantly increase the hoarding intensity of small-sized species and show a unidirectional pilferage of seeds cached by small-sized species. The behavioural differences between these two species may reduce competition for resources and promote coexistence between sympatric rodents.

The life history of Cyclops scutifer Sars (Copepoda: Cyclopoida) in a small lake of the Matamek River System, Quebec

1978 ◽  
Vol 56 (12) ◽  
pp. 2603-2607 ◽  
Author(s):  
J. J. Boers ◽  
J. C. H. Carter
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Calanoid Copepod ◽  
River System ◽  
The Other ◽  
Cyclopoid Copepod ◽  
Small Lake ◽  
History Of ◽  
Cyclops Scutifer ◽  
Copepoda Cyclopoida

A study of the life history of the cyclopoid copepod Cyclops scutifer Sars in a small lake of the Matamek River System, Quebec, indicates a 1-year life cycle with four cohorts produced annually. The primary cohort overwinters as early nauplii and reaches maturity during midsummer when it spawns the primary cohort of the succeeding year. The other cohorts may merge with either each other or the primary cohort and contribute somewhat less to the overall cycle. Slower development of copepodites of the second cohort in 1976 may have been the result of an inadequate number of naupliar prey from the calanoid copepod Diaptomus minutus.

Performance of Domestic, Hybrid, and Wild Strains of Brook Trout, Salvelinus fontinalis, after Stocking: the Impact of Intra- and Interspecific Competition

1990 ◽  
Vol 47 (12) ◽  
pp. 2278-2284 ◽  
Author(s):  
Stephanie Lachance ◽  
Pierre Magnan
Keyword(s):  
Interspecific Competition ◽  
Relative Abundance ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Oligotrophic Lakes ◽  
Wild Strains ◽  
The Impact ◽  
Response Variables

Wild and hybrid strains of brook trout, Salvelinus fontinalis, showed better rates of recovery (by angling) and yield (kilograms of fish recovered per kilogram planted) than a domestic strain, during the 2 yr following planting, in six small oligotrophic lakes of the Laurentian Shield. Native brook trout and white sucker, Catostomus commersoni, had a significant impact on planted brook trout. Recovery, percent of increment in weight and yield of each planted strain were inversely correlated with (1) the relative abundance of native brook trout, and (2) the occurrence of white sucker, supporting hypotheses of intra- and interspecific competition. Furthermore, the response variables were also inversely correlated with the number of potential competitors, indicating that the impact of native brook trout and white sucker was additive. The recovery in number of planted trout (both years and all strains) was approximately four times higher in lakes with effectively no competitors than in lakes containing both white sucker and native brook trout; the increase in weight was nearly three times higher, and the yield was more than nine times higher. The performances of planted fish were intermediate in the lake containing only native brook trout as competitor.

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