Reproductive Isolation Between the Sunfish Lepomis gibbosus and L. macrochirus

1967 ◽  
Vol 24 (3) ◽  
pp. 495-514 ◽  
Author(s):  
Francis W. Clark ◽  
Miles H. A. Keenleyside
Keyword(s):  
Reproductive Isolation ◽  
Visual Recognition ◽  
Nest Site Selection ◽  
Lepomis Gibbosus ◽  
Major Barrier ◽  
Interspecific Differences ◽  
Large Numbers ◽  
Interspecific Courtship ◽  
Ethological Isolation ◽  
Breeding Seasons

Reproductive isolation appeared to be complete between pumpkinseeds (Lepomis gibbosus) and bluegills (L. macrochirus) when equal numbers (1:1 sex ratio) were stocked in each of two similar ponds near London, Ontario, and observed during the breeding seasons of 1964 and 1965. Ethological isolation, through visual recognition of potential conspecific mates, was probably the major barrier to hybridization. Interspecific courtship and attempted spawning were not seen; intraspecific courtship and spawning were frequently observed. No clearly identifiable hybrids were found among large numbers of yearling and 2-year-old offspring collected in both ponds in 1965 and 1966.Pumpkinseeds began nesting about 3 weeks before bluegills, but spawning by the two species broadly overlapped in time both years. Individual pumpkinseeds occupied nests for an average of 18.5 days; bluegills for 8.7 days. Duration of pumpkinseed nest occupancy appeared to vary directly with surface water temperature, whether eggs or fry were in the nests or not, whereas bluegills tended to remain on nests containing eggs or fry, regardless of temperature fluctuations. Bluegills nested in deeper water and further from shore than pumpkinseeds, and bluegills tended to nest in colonies whereas pumpkinseeds did not. Interspecific differences were not found in nest site selection with respect to substrate or vegetation.

Reproductive Isolation Between Pumpkinseed (Lepomis gibbosus) and Longear Sunfish (L. megalotis) (Centrarchidae) in the Thames River, Southwestern Ontario

1978 ◽  
Vol 35 (1) ◽  
pp. 131-135 ◽  
Author(s):  
Miles H. A. Keenleyside
Keyword(s):  
Reproductive Isolation ◽  
Water Flow ◽  
Lepomis Gibbosus ◽  
Main River ◽  
Longear Sunfish ◽  
Sand And Gravel ◽  
Breeding Seasons ◽  
Thames River ◽  
Behavioral Barriers ◽  
Interspecific Breeding

In the middle branch of the Thames River, southwestern Ontario, nest construction and occupation by male pumpkinseeds (Lepomis gibbosus) began earlier and reached a peak earlier in the season than nesting by male longear sunfish (L. megalotis). Nevertheless the two species' breeding seasons broadly overlapped. All pumpkinseed nests occurred in backwater areas, where water flow is minimal, the substrate is a deep layer of detritus and mud, and aquatic plant growth is heavy. Some longear nests were in the backwaters, but most were in the main river, where water flow is variable, the substrate mainly sand and gravel, and vegetation sparse. Females of both species are nonterritorial and were found throughout the study area. Hybrid sunfish are present in the area and opportunities for interspecific breeding would seem to be greatest in backwaters, where males of both species may occupy nests close to each other. However, the only observed interbreeding was between female pumpkinseeds and male longears in the main river. Behavioral barriers to interbreeding occasionally break down under the turbulent social conditions associated with breeding in large longear colonies. Key words: sunfish, reproductive isolation, longear, pumpkinseed, habitat, season, behavior

scholarly journals Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species

2020 ◽  
Author(s):  
Tetsuya K Matsumoto ◽  
Muneto Hirobe ◽  
Masahiro Sueyoshi ◽  
Yuko Miyazaki
Keyword(s):  
Reproductive Isolation ◽  
Altitudinal Gradient ◽  
Flowering Phenology ◽  
Altitudinal Distribution ◽  
Interspecific Differences ◽  
Flower Visitation ◽  
Fungus Gnats ◽  
Floral Visitor ◽  
Floral Visitors ◽  
Experimental Plots

Abstract Background and Aims Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. Methods We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. Key Results Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Conclusions Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

BIOSYSTEMATICS OF THE GENUS EUXOA (LEPIDOPTERA: NOCTUIDAE). XVIH. COMPARATIVE BIOLOGY AND EXPERIMENTAL TAXONOMY OF THE SIBLING SPECIES EUXOA RIDMGSIANA (GRT.) AND EUXOA MAIMES (SM.)

1985 ◽  
Vol 117 (4) ◽  
pp. 481-493 ◽  
Author(s):  
J.R. Byers ◽  
D.L. Struble ◽  
J.D. Lafontaine
Keyword(s):  
Life Cycle ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Mate Recognition ◽  
Recognition System ◽  
Flight Period ◽  
Interspecific Differences ◽  
Mate Recognition System ◽  
The Difference ◽  
Species Specific

AbstractThe species previously recognized as Euxoa ridingsiana (Grt.) is shown to be composed of a sympatric pair of sibling species, Euxoa ridingsiana (Grt.) and Euxoa maimes (Sm.), which in the laboratory will produce viable F1 hybrids but no F2. Results of F1 sib and backcrosses show that the F1 males are fertile and the F1 females are infertile. In mating-bias tests conducted in laboratory cages, 74% of matings were conspecific and 26% interspecific. Differences in the diel periodicities of mating, which are about 2 h out of phase, may account for the mating bias. The duration of development of E. ridingsiana in the laboratory and its seasonal flight period in the field are about 2 weeks in advance of that of E. maimes. However, there is considerable overlap of the flight periods and, with the tendency of females of both species to mate several times, it is unlikely that the difference in seasonal emergence is enough to effect reproductive isolation. It is evident that, under natural conditions, reproductive isolation can be maintained entirely by species-specific sex pheromones. This mechanism of reproductive isolation is, however, apparently ineffective when moths are confined in cages in the laboratory.Biogeographic considerations suggest that the differences in life-cycle timing and mating periodicities might have been adaptations to adjust development and reproduction to prevailing ancestral environments. If the initial differentiation of the 2 species occurred in isolation and included at least an incipient shift in the pheromonal mate-recognition system, it is possible that upon reestablishment of contact between ancestral populations the differences in life-cycle timing and mating periodicities acting in concert could have effected substantial, albeit incomplete, reproductive isolation. Subsequent selection to reinforce assortative mating to preserve coadapted gene complexes could then have resulted in differentiation of discrete pheromonal systems and attainment of species status.

scholarly journals An olfactory receptor gene underlies reproductive isolation in perfume-collecting orchid bees

2019 ◽  
Author(s):  
P. Brand ◽  
I. A. Hinojosa-Díaz ◽  
R. Ayala ◽  
M. Daigle ◽  
C. L. Yurrita Obiols ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Odorant Receptor ◽  
Receptor Gene ◽  
Rapid Evolution ◽  
Natural Populations ◽  
Reproductive Barriers ◽  
Species Identity ◽  
Orchid Bees ◽  
Major Barrier ◽  
Genetic Mechanisms

Speciation is facilitated by the evolution of reproductive barriers that prevent or reduce hybridization among diverging lineages. However, the genetic mechanisms that control the evolution of reproductive barriers remain elusive, particularly in natural populations. We identify a gene associated with divergence in chemical courtship signaling in a pair of nascent orchid bee lineages. Male orchid bees collect perfume compounds from flowers and other sources to subsequently expose during courtship display, thereby conveying information on species identity. We show that these two lineages exhibit differentiated perfume blends and that this change is associated with the rapid evolution of a single odorant receptor gene. Our study suggests that reproductive isolation evolved through divergence of a major barrier gene involved in chemically mediated pre-mating isolation via genetic coupling.

“Parthenogenesis” in Schistosoma mattheei

1969 ◽  
Vol 43 (1-2) ◽  
pp. 197-206 ◽  
Author(s):  
M. G. Taylor ◽  
M. B. A. Amin ◽  
G. S. Nelson
Keyword(s):  
Reproductive Isolation ◽  
Experimental Studies ◽  
Biological Significance ◽  
Considerable Proportion ◽  
Mixed Infections ◽  
Transmission Potential ◽  
Single Sex ◽  
Large Numbers ◽  
Rectal Biopsies ◽  
Full Maturity

Experimental studies in mice have shown that with single sex female infections of S. mattheei there is a slow maturation of the worms with evidence of incomplete parthenogenesis; at 9 weeks no eggs were produced but at 17 weeks there was an average of 500 eggs per mouse. These were all non viable. Under similar conditions S. mansoni females failed to produce eggs.When the females of S. mattheei were paired with males of S. mansoni, the females reached full maturity and produced large numbers of eggs typical of their own species-many of the eggs were non viable but some contained active miracidia.It is considered that this is an example of parthenogenesis and not hybridisation. Cross specific pairings of schistosomes must occur frequently in man particularly with S. haematobium, S. mansoni and S. mattheei and this phenomenon could be of considerable clinical, epidemiological and biological significance. Parthenogenesis in mixed infections probably accounts for the large number of non-viable S. haematobium eggs seen in rectal biopsies, and it may also be important in reducing the transmission potential of schistosomes to man since cross pairing must result in the “sterilisation” of a considerable proportion of the female worms in mixed infections. This phenomenon may also explain the observed reproductive isolation of schistosome species which simultaneously infect the same host.

Courtship and mating behaviours of two syntopic species of skink (Plestiodon anthracinus and Plestiodon fasciatus)

2007 ◽  
Vol 28 (2) ◽  
pp. 263-268
Author(s):  
Robert Alexander Pyron ◽  
Carlos Duane Camp
Keyword(s):  
Survival Analysis ◽  
Related Species ◽  
Chemical Cues ◽  
Closely Related Species ◽  
Interspecific Differences ◽  
Isolating Mechanisms ◽  
Plestiodon Fasciatus ◽  
Ethological Isolation

AbstractCourtship and mating behaviours are widely conserved throughout the scincid lizard genus Plestiodon, and ethological isolation between closely related species depends heavily on differentiating chemical cues. The purpose of this study was to determine whether or not subtle, as yet undetected differences are present in the mating behaviours of two syntopic, distantly related skinks, P. anthracinus and P. fasciatus. Observed courtship and mating behaviours were similar between the two species and to those reported for other species within this genus. However, survival analysis determined significant interspecific differences in the duration of pre-coital behaviours. Investigation of such subtle differences between species more closely related than these two may generate further insights into the evolution of ethological isolating mechanisms in lizards.

Role of Woody Debris in Nest Site Selection by Pumpkinseed Sunfish, Lepomis gibbosus

1973 ◽  
Vol 30 (6) ◽  
pp. 853-856 ◽  
Author(s):  
Patrick Colgan ◽  
David Ealey
Keyword(s):  
Nearest Neighbor ◽  
Woody Debris ◽  
Breeding Population ◽  
Nest Site Selection ◽  
Lepomis Gibbosus ◽  
Nest Density ◽  
Spawning Activity ◽  
Pumpkinseed Sunfish ◽  
Nearest Neighbor Distances

Nesting preference for areas cleared of woody debris over areas cluttered with such debris was indicated by more nesting in cleared areas at the beginning and end of the breeding season, and more spawning activity in cleared areas. During heavy nesting, however, no preference was observed due to the density-dependent constraint of a high breeding population limiting available nesting space. This lack of difference in nesting densities at peak times indicates that breeding density cannot be enhanced in pumpkinseed sunfish by the creation of additional environmental boundaries. Nest density was influenced by the type of substrate of the site. In cluttered sections, nest diameters and distances to nearest cover were less than, and nearest neighbor distances not significantly different from, those in cleared sections.

scholarly journals Reproductive isolation among three populations of the genus Grammostola from Uruguay (Araneae, Theraphosidae)

2006 ◽  
Vol 96 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Rodrigo Postiglioni ◽  
Fernando G. Costa
Keyword(s):  
Reproductive Isolation ◽  
Southern Population ◽  
Northern Population ◽  
Laboratory Conditions ◽  
Ethological Isolation ◽  
Two Populations ◽  
Isolated Species

Ethological isolation of individuals from three allopatric Grammostola populations of Uruguay, G. iheringi (Keyserling, 1891), G. mollicoma (Auserer, 1875) northern population and G. mollicoma southern population, was tested under laboratory conditions. Grammostola iheringi behaved as a reproductive isolated species, whereas the two populations of G. mollicoma did not show ethological isolation between them. However, ecological isolating reproductive mechanisms could be acting on G. mollicoma populations. Artificial burrows seem to be important for reproductive isolation in these species.

Levels of male aggressiveness in fluctuating populations of Microtus ochrogaster and M. pennsylvanicus

1982 ◽  
Vol 60 (5) ◽  
pp. 898-912 ◽  
Author(s):  
Joyce E. Hofmann ◽  
Lowell L. Getz ◽  
Brian J. Klatt
Keyword(s):  
Microtus Ochrogaster ◽  
Behavioral Data ◽  
Population Cycle ◽  
Field Phase ◽  
Polymorphic Behavior ◽  
Free Living ◽  
Large Numbers ◽  
Behavioral Variables ◽  
Fluctuating Populations ◽  
Breeding Seasons

Levels of male aggressiveness, determined by observation of dyadic encounters, were compared during low, increase, peak, and decline phases of the population cycle in free-living populations of Microtus ochrogaster and M. pennsylvanicus. There were no significant differences in the proportions of nonaggressive, aggressive, and highly aggressive males during the low, increase, and peak phases of M. ochrogaster populations in an alfalfa and in a bluegrass habitat. Large numbers of nonaggressive voles were present during the decline phases. The aggressiveness of individual males appeared greater at peak densities only in the bluegrass field. Phase of cycle explained 18.6% of the variation in behavioral variables for the bluegrass area population and 5.8% for the alfalfa area population. The proportions of aggressive types for M. pennsylvanicus populations in bluegrass and prairie habitats did not vary significantly with phase of the population cycle and there was no indication of an increased level of individual aggressiveness at peak densities. Phase of cycle explained 25.2% of the variation in behavioral data for the bluegrass area population and 12.2% for the prairie population. Seasonal heterogeneity was found in the behavior of M. ochrogaster and season accounted for more of the behavioral variation in each population than had phase of cycle. Although seasonal trends were not entirely consistent, the data suggested that males may be more aggressive in winter and autumn. For M. pennsylvanicus the proportions of nonaggressive males were lower during spring and autumn (which correspond to the breeding seasons) than during summer and winter. The results of the present study were not consistent with the polymorphic behavior hypothesis.

scholarly journals Nesting information for Tropeiro Seedeater (Sporophila beltoni), an endemic songbird from southern Brazil

2019 ◽  
Vol 27 (3) ◽  
pp. 164-168
Author(s):  
Márcio Repenning ◽  
Carla Suertegaray Fontana
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Site Selection ◽  
Southern Brazil ◽  
Spider Webs ◽  
Breeding Seasons

AbstractWe present the first nesting information for the Tropeiro Seedeater (Sporophila beltoni), a newly described and poorly known Neotropical passerine endemic to southern Brazil. We observed a novel male biased behavior for nest site selection in the Tropeiro Seedeater based on seven events of pre-nesting display courtship. We describe the nest, eggs, nestlings, and fledglings based on 133 nests found over four breeding seasons (2007 to 2011). The nest is a cup-shaped structure made with dry grass inflorescences and spider webs. It is placed in low, forked branches of substrate shrubs and contains multiple attachment points. The eggs are typically white with dark spots or stripes, and are pyriform in shape. Average egg dimensions are 18.2 × 13.2 mm. Nestlings fledge after 10 days. We provide the key information for distinguishing the nest, eggs, nestlings and fledglings of S. beltoni from other sympatric Sporophila species.

Sign in / Sign up

Export Citation Format

Share Document