scholarly journals Longer Sperm Swim More Slowly in the Canary Islands Chiffchaff

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1358
Author(s):  
Emily R. A. Cramer ◽  
Eduardo Garcia-del-Rey ◽  
Lars Erik Johannessen ◽  
Terje Laskemoen ◽  
Gunnhild Marthinsen ◽  
...  
Keyword(s):  
Canary Islands ◽  
Swimming Speed ◽  
Sperm Morphology ◽  
Swimming Performance ◽  
Fertilization Success ◽  
Sperm Length ◽  
Gran Canaria ◽  
Island Populations ◽  
Motile Cells ◽  
Sperm Swimming Speed

Sperm swimming performance affects male fertilization success, particularly in species with high sperm competition. Understanding how sperm morphology impacts swimming performance is therefore important. Sperm swimming speed is hypothesized to increase with total sperm length, relative flagellum length (with the flagellum generating forward thrust), and relative midpiece length (as the midpiece contains the mitochondria). We tested these hypotheses and tested for divergence in sperm traits in five island populations of Canary Islands chiffchaff (Phylloscopus canariensis). We confirmed incipient mitochondrial DNA differentiation between Gran Canaria and the other islands. Sperm swimming speed correlated negatively with total sperm length, did not correlate with relative flagellum length, and correlated negatively with relative midpiece length (for Gran Canaria only). The proportion of motile cells increased with relative flagellum length on Gran Canaria only. Sperm morphology was similar across islands. We thus add to a growing number of studies on passerine birds that do not support sperm morphology–swimming speed hypotheses. We suggest that the swimming mechanics of passerine sperm are sufficiently different from mammalian sperm that predictions from mammalian hydrodynamic models should no longer be applied for this taxon. While both sperm morphology and sperm swimming speed are likely under selection in passerines, the relationship between them requires further elucidation.

Reduced sperm performance in backcross hybrids between species pairs of whitefish (Coregonus clupeaformis)

2009 ◽  
Vol 87 (7) ◽  
pp. 566-572 ◽  
Author(s):  
A. R. Whiteley ◽  
K. N. Persaud ◽  
N. Derome ◽  
R. Montgomerie ◽  
L. Bernatchez
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Fertilization Success ◽  
F1 Hybrids ◽  
Coregonus Clupeaformis ◽  
External Fertilization ◽  
Isolating Mechanisms ◽  
Species Pairs ◽  
Backcross Hybrids ◽  
Sperm Swimming Speed

Previous work has demonstrated that genomic incompatibilities work together with ecologically divergent selection to promote and maintain reproductive isolation between incipient species (dwarf and normal) of lake whitefish ( Coregonus clupeaformis (Mitchill, 1818)). Whitefish spawn in groups with external fertilization, which creates conditions for strong sperm competition. In this study, we asked whether reduced sperm performance in hybrids from whitefish species-pair matings might contribute to postzygotic isolating mechanisms between these taxa. We examined two sperm traits, sperm swimming speed and flagellum length, in pure dwarf and normal whitefish and in their F1 and backcross hybrids. We observed significantly reduced sperm swimming speed in backcross but not in F1 hybrids. Sperm flagellum length was not significantly correlated with sperm swimming speed. These results demonstrate that F1 hybrids formed in nature should be capable of the same fertilization success as the parental species during sperm competition, everything else being equal. However, reduced sperm performance in the backcross generation is consistent with other evidence suggesting that genomic incompatibilities create a range of negative fitness effects in post-F1 whitefish hybrids and provides evidence for an additional postzygotic isolation mechanism involved in the incipient speciation of sympatric dwarf and normal whitefish.

Sperm quality influences male fertilization success in walleye (Sander vitreus)

2006 ◽  
Vol 63 (9) ◽  
pp. 2119-2125 ◽  
Author(s):  
Stephen J Casselman ◽  
Albrecht I Schulte-Hostedde ◽  
Robert Montgomerie
Keyword(s):  
Swimming Speed ◽  
Sperm Quality ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Sander Vitreus ◽  
External Fertilization ◽  
Theoretical Predictions ◽  
Sperm Swimming Speed ◽  
Experimental Trials ◽  
Success Percentage

We examined how variation in sperm quality influences a male's success at fertilizing ova (male fertilization success) in a wild population of walleye (Sander vitreus). To do this, we conducted controlled fertilization trials using milt and eggs (ova) from wild-spawning fish and measured male fertilization success (percentage of ova fertilized) by examining eggs after 24 h of incubation. We found that both the number of sperm and sperm swimming speed (at 10 s after activation) were significantly related to fertilization success. There was, with respect to fertilization success, a relatively large return on male investment in the number of sperm, but this return diminished as the percentage of ova fertilized increased above 50%. This is in agreement with theoretical predictions based on external fertilization dynamics. When the number of sperm used in the experimental trials was kept constant, variation in sperm swimming speed (at 10 s after activation) explained approximately 90% of the variation in a male's fertilization success. These findings demonstrate that the variation in sperm quality found in wild spawning populations has the potential to dramatically influence male reproductive success.

scholarly journals Sperm performance under hypoxic conditions in the intertidal fish Porichthys notatus

2009 ◽  
Vol 87 (5) ◽  
pp. 464-469 ◽  
Author(s):  
John L. Fitzpatrick ◽  
Paul M. Craig ◽  
Carol Bucking ◽  
Sigal Balshine ◽  
Chris M. Wood ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Fertilization Success ◽  
Reproductive Hormones ◽  
Reproductive Capacity ◽  
Low Oxygen ◽  
Hypoxic Conditions ◽  
Porichthys Notatus ◽  
Sperm Swimming Speed ◽  
Plainfin Midshipman

Hypoxia (low oxygen) exposure generally leads to decreased reproductive capacity, exhibited by reductions in testicular mass, reproductive hormones, and sperm swimming speed. However, in many fish species, reproduction occurs either periodically or exclusively under hypoxic conditions. In this study we assessed how hypoxia influences sperm performance in the plainfin midshipman ( Porichthys notatus Girard, 1854), a species that lives in intertidal nests that become hypoxic during low tides. We exposed sperm from the same male to normoxic or hypoxic conditions and compared sperm characteristics and oxygen consumption between treatments. Sperm exposed to hypoxic water swam faster and consumed more oxygen than sperm swimming in normoxic conditions. Sperm swimming speed was positively related with oxygen consumption. For each male, the percentage of motile spermatozoa did not differ between treatments, suggesting that the same number of sperm were active but their performance was dependent on the dissolved oxygen content in the water. We discuss the implications of our results in the context of sperm competition and fertilization success under hypoxic conditions.

Impact of Diet on Metabolism and Swimming Performance in Juvenile Lake Trout, Salvelinus namaycush

1989 ◽  
Vol 46 (3) ◽  
pp. 384-388 ◽  
Author(s):  
F. W. H. Beamish ◽  
J. C. Howlett ◽  
T. E. Medland
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Lake Trout ◽  
Swimming Performance ◽  
Salvelinus Namaycush ◽  
Feeding Trial ◽  
Direct Association ◽  
Feeding Trials ◽  
Velocity Increments ◽  
Isocaloric Diets

Juvenile lake trout, Salvelinus namaycush, of similar size were fed one of three isocaloric diets, each differing in protein and lipid content. Oxygen consumption and swimming performance were measured in a recirculating water flume at intervals throughout the 70-d feeding trials (10 °C). Swimming speed was increased by stepwise velocity increments (5 cm∙s−1) and oxygen consumption was measured at each velocity between 20 and 45 cm∙s−1. Oxygen consumption for a given speed did not differ significantly throughout the feeding trial nor among the diets implying a similarity in the quality and quantity of substrate catabolized for energy. Basal metabolism (0 cm∙s−1) was also independent of diet and feeding interval. Critical swimming speed increased with dietary and carcass protein content to suggest a direct association with muscle mass and number of myofilaments.

scholarly journals Feeding strategy of mackerel in the Norwegian Sea relative to currents, temperature, and prey

2015 ◽  
Vol 73 (4) ◽  
pp. 1127-1137 ◽  
Author(s):  
Leif Nøttestad ◽  
Justine Diaz ◽  
Hector Penã ◽  
Henrik Søiland ◽  
Geir Huse ◽  
...  
Keyword(s):  
Swimming Speed ◽  
Swimming Performance ◽  
Feeding Strategy ◽  
Near Field ◽  
Norwegian Sea ◽  
Swimming Direction ◽  
Atlantic Mackerel ◽  
The North ◽  
Foraging Rate ◽  
Feeding Resources

Abstract High abundance of Northeast Atlantic mackerel (Scomber scombrus L.), combined with limited food resources, may now force mackerel to enter new and productive regions in the northern Norwegian Sea. However, it is not known how mackerel exploit the spatially varying feeding resources, and their vertical distribution and swimming behaviour are also largely unknown. During an ecosystem survey in the Norwegian Sea during the summer feeding season, swimming direction, and speed of mackerel schools were recorded with high-frequency omnidirectional sonar in four different regions relative to currents, ambient temperature, and zooplankton. A total of 251 schools were tracked, and fish and zooplankton were sampled with pelagic trawl and WP-2 plankton net. Except for the southwest region, swimming direction of the tracked schools coincided with the prevailing northerly Atlantic current direction in the Norwegian Sea. Swimming with the current saves energy, and the current also provides a directional cue towards the most productive areas in the northern Norwegian Sea. Average mean swimming speed in all regions combined was ∼3.8 body lengths s−1. However, fish did not swim in a straight course, but often changed direction, suggesting active feeding in the near field. Fish were largest and swimming speed lowest in the northwest region which had the highest plankton concentrations and lowest temperature. Mackerel swam close to the surface at a depth of 8–39 m, with all schools staying above the thermocline in waters of at least 6°C. In surface waters, mackerel encounter improved foraging rate and swimming performance. Going with the flow until temperature is too low, based on an expectation of increasing foraging rate towards the north while utilizing available prey under way, could be a simple and robust feeding strategy for mackerel in the Norwegian Sea.

New records of naturalised and invasive cacti (Cactaceae) from Gran Canaria and Tenerife, Canary Islands, Spain

Bradleya ◽  
2017 ◽  
Vol 35 (35) ◽  
pp. 58-79 ◽  
Author(s):  
Filip Verloove ◽  
Elizabeth Ojeda-Land ◽  
Gideon F. Smith ◽  
Alessandro Guiggi ◽  
Jorge Alfredo Reyes-Betancort ◽  
...  
Keyword(s):  
Canary Islands ◽  
New Records ◽  
Gran Canaria

THE EFFECT OF SOLID AND POROUS CHANNEL WALLS ON STEADY SWIMMING OF STEELHEAD TROUT ONCORHYNCHUS MYKISS

1993 ◽  
Vol 178 (1) ◽  
pp. 97-108 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Swimming Speed ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Regression Coefficients ◽  
Steelhead Trout ◽  
Wall Effects ◽  
Fish Swimming ◽  
Wide Channel ◽  
Solid Walls ◽  
Tail Beat

Kinematics and steady swimming performance were recorded for steelhead trout (approximately 12.2 cm in total length) swimming in channels 4.5, 3 and 1.6 cm wide in the centre of a flume 15 cm wide. Channel walls were solid or porous. Tail-beat depth and the length of the propulsive wave were not affected by spacing of either solid or porous walls. The product of tail-beat frequency, F, and amplitude, H, was related to swimming speed, u, and to harmonic mean distance of the tail from the wall, z. For solid walls: FH = 1.01(+/−0.31)u0.67(+/−0.09)z(0.12+/−0.02) and for grid walls: FH = 0.873(+/−0.302)u0.74(+/−0.08)z0.064(+/−0.024), where +/−2 s.e. are shown for regression coefficients. Thus, rates of working were smaller for fish swimming between solid walls, but the reduction due to wall effects decreased with increasing swimming speed. Porous grid walls had less effect on kinematics, except at low swimming speeds. Spacing of solid walls did not affect maximum tail-beat frequency, but maximum tail-beat amplitude decreased with smaller wall widths. Maximum tail-beat amplitude similarly decreased with spacing between grid walls, but maximum tail-beat frequency increased. Walls also reduced maximum swimming speed. Wall effects have not been adequately taken into account in most studies of fish swimming in flumes and fish wheels.

scholarly journals New xenophytes from the Canary Islands (Gran Canaria and Tenerife; Spain)

2017 ◽  
Vol 76 (2) ◽  
pp. 120-131 ◽  
Author(s):  
Filip Verloove
Keyword(s):  
Canary Islands ◽  
Vascular Plant ◽  
Psidium Guajava ◽  
Nerium Oleander ◽  
Gran Canaria ◽  
Cyperus Difformis ◽  
Eclipta Prostrata ◽  
Callistemon Viminalis ◽  
Eucalyptus Gomphocephala ◽  
Chloris Barbata

Abstract Recent fieldwork in Gran Canaria and Tenerife (Canary Islands, Spain), mostly between 2012 and 2016, yielded new chorological data for several non-native vascular plant species. The following are considered naturalized and/or potentially invasive: Callistemon viminalis, Casuarina glauca, Chloris barbata, Cyperus difformis, Eucalyptus gomphocephala, E. sideroxylon, Nephrolepis cordifolia, Rumex palustris, Senna × artemisioides (s.l.) and S. × floribunda and are reported for the first time from the Canary Islands. Other first records include: Cascabela thevetia (Tenerife), Cyclospermum leptophyllum (Gran Canaria), Digitaria radicosa (Gran Canaria, Tenerife), Dysphania anthelmintica (Tenerife), Erythrostemon gilliesii (Tenerife), Heliotropium supinum (Tenerife), Limoniastrum monopetalum (Tenerife), Nerium oleander (Tenerife), Pascalia glauca (Tenerife), Phytolacca americana (Tenerife), Podranea ricasoliana (Gran Canaria), Psidium guajava (Gran Canaria), Rumex cristatus (Tenerife), Schinus terebinthifolia (Tenerife), Solandra maxima (Tenerife), Tipuana tipu (Tenerife) and Youngia japonica (Gran Canaria). More than 20 additional taxa also represent chorological novelties but are considered ephemerals. Finally, miscellaneous notes are added for Diplachne fusca subsp. uninervia, Eclipta prostrata, Pluchea carolinensis, Prosopis juliflora and Sida rhombifolia from Gran Canaria.

scholarly journals Los soldados del presidio de Gran Canaria en el siglo xvi/

Cliocanarias ◽  
2021 ◽  
pp. 1-33
Author(s):  
Manuel Lobo Cabrera ◽  
Keyword(s):  
Canary Islands ◽  
Gran Canaria

The study of the militias in the Canary archipelago has been a recurring theme in insular historiography, addressed by different authors in breadth and depth, covering not only their organization but also the strategy and weapons used in moments of danger. However, the presence of the presidios in the Canary Islands has had fewer options, as they are professional troops, passing through and reinforcement, that operate on the islands at specific times. The objective, therefore, that we pursue in this study is. in the development of Gran Canaria defense, to oppose the two types of forces that operated in its territory and their characteristics and consequences.

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