Effects of ovarian fluid on sperm velocity in Arctic charr ( Salvelinus alpinus )

Numbers of studies in externally fertilizing fish species provide evidence for an effect of ovarian fluid on sperm motility characteristics such as duration of forward mobility, velocity or percent motile sperm cells. Yet, because of variations among females in the quality of their ovarian fluid, such effects might differ between individuals. Additionally, ovarian fluid from different females could also be expected to affect each ejaculate differently, resulting in cryptic female choice. In this study on Artic charr (Salvelnius alpinus), sperm velocity from several males was measured in the diluted ovarian fluid of several females according to a fully balanced crossing design. This design allowed us to estimate variations among females in the effect of their ovarian fluid on the velocity of sperm from different males, and to detect variations among males in the ability of their sperm to swim in ovarian fluid. Sperm velocity was estimated by computer-assisted sperm analysis. Average velocity was found to vary among females, with some females having constantly higher velocity measurements in their ovarian fluid, and among males, indicating that some males had overall faster sperm in ovarian fluid than others. Moreover, variation in sperm velocity was shown to depend on individual female-male interactions. Our results document that females vary in the effect of their ovarian fluid on sperm velocity and that their ovarian fluid may stimulate sperm velocity according to individual characteristics of males. This latter result suggests a potential mechanism for cryptic female choic

Own,but not foreign seminal fluid inhibits sperm activation in a vertebrate with external fertilization

This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.Seminal fluids are known to have a variety of effects on rival sperm, but in externally fertilizing species it is still unclear what effects seminal fluid can induce under sperm competition. We recorded sperm activity from natural ejaculates (including own seminal fluid) of an external fertilizer, the Arctic charr (Salvelinus alpinus), after activation either in water (the natural medium for milt dilution), in a dilution of water and own seminal fluid or in a dilution of water and seminal fluid of a foreign male. When activation occurred in own or foreign dilutions of seminal fluids, sperm maintained higher velocities than when activated in water only. Yet, velocity did not differ depending on whether sperm was activated in own or foreign seminal fluid solutions. More important, approximately 25% fewer sperm cells were initially activated in own seminal fluid than in foreign seminal fluid or water, indicating that activation is under close control of own seminal fluid only. Our results document that the presence of foreign seminal fluid under sperm competition do not have apparent effect on sperm velocity. Yet, the large inhibitory effect on initial activation of sperm cells seen in own, but not in foreign dilutions of seminal fluids (and water) suggests an individual specific recognition mechanism exerted by something in the seminal fluid on own, but not foreign sperm cells. The importance of this extrasomatic sperm recognition for the outcome of sperm competitions is discussed

Predicting the mating system from phenotypic correlations between life-history and sperm quality traits in the Alpine whitefish Coregonus zugensis

The mating behavior and reproductive strategies of Alpine whitefish like Coregonus zugensis (Nüsslin) are poorly understood, probably because they spawn in deep water where direct observations are difficult. In this study, we interpret life-history and sperm quality traits of fish that we caught from their spawning place. We found that males invest heavily into gonadal tissue (up to 5.6% of their body weight), which is, in comparison to other fish, consistent with external fertilization, distinct pairing and moderate to high communal spawning, or no pairing and low to moderate communal spawning. Sperm competition theory and recent experimental studies on other salmonids predict that males optimize ejaculate characteristics in relation to the costs of sperm and the level of competition they have to expect: dominant males are predicted to invest less into ejaculate quality and to have slower spermatozoa than subdominant males. We found that spermatozoa of older males are slower than those of younger males. Moreover, older males have larger breeding tubercles, a secondary sexual trait that has, in some previous studies, been found to be linked to good condition and to good genetic quality. Our results suggest that C. zugensis has age-linked reproductive strategies, that multimale spawning is common, i.e., that sperm competition plays a significant role, and that older males are on average dominant over younger males at the spawning plac

Yellowhammer Emberiza citrinella nesting in reed Phragmites australis

Hekkende gulspurv over vannflaten i takrørskogI forbindelse med feltarbeid ved Hellesjøvatnet i Aurskog-Høland kommune, Akershus fylke, fant vi et reir fra gulspurv i takrørskogen. Reiret ble funnet den 22. juni 2002 og var festet mellom noen stammer fra takrør. Deler av gammelt takrør var brukket og fungerte som plattform for reiret. Gulspurven plasserer sitt reir som oftest på bakken eller i busker og små trær opp til omtrent en halv meter over bakken. Reir i busker og små trær er vanligere utover i hekkesesongen, noe som skjuler reiret. I vårt tilfelle lå reiret godt beskyttet for bakkelevende predatorer, men meget åpent til for predasjon av fugler. Det kan også være forklaringen på at, så vidt vi vet, det tidligere ikke er beskrevet at gulspurven plasserer reiret sitt rett over vannflaten i takrør

Sperm velocity in a promiscuous bird across experimental media of different viscosities

Schmoll T, Rudolfsen G, Schielzeth H, Kleven O. Sperm velocity in a promiscuous bird across experimental media of different viscosities. Proceedings of the Royal Society B: Biological Sciences. 2020;287(1931): 20201031.In species with internal fertilization, the female genital tract appears challenging to sperm, possibly resulting from selection on for example ovarian fluid to control sperm behaviour and, ultimately, fertilization. Few studies, however, have examined the effects of swimming media viscosities on sperm performance. We quantified effects of media viscosities on sperm velocity in promiscuous willow warblers Phylloscopus trochilus. We used both a reaction norm and a character-state approach to model phenotypic plasticity of sperm behaviour across three experimental media of different viscosities. Compared with a standard medium (Dulbecco's Modified Eagle Medium, DMEM), media enriched with 1% or 2% w/v methyl cellulose decreased sperm velocity by up to about 50%. Spermatozoa from experimental ejaculates of different males responded similarly to different viscosities, and a lack of covariance between elevations and slopes of individual velocity-by-viscosity reaction norms indicated that spermatozoa from high- and low-velocity ejaculates were slowed down by a similar degree when confronted with high-viscosity environments. Positive cross-environment (1% versus 2% cellulose) covariances of sperm velocity under the character-state approach suggested that sperm performance represents a transitive trait, with rank order of individual ejaculates maintained when expressed against different environmental backgrounds. Importantly, however, a lack of significant covariances in sperm velocity involving a cellulose concentration of 0% indicated that pure DMEM represented a qualitatively different environment, questioning the validity of this widely used standard medium for assaying sperm performance. Enriching sperm environments along ecologically relevant gradients prior to assessing sperm performance will strengthen explanatory power of in vitro studies of sperm behaviour

Status specific tailoring of sperm behavior in an external fertilizer

Published version. Source at https://doi.org/10.3389/fevo.2016.00135 Why dominant males experiencing intense sperm competition sometimes show low investments in sperm production is not always obvious. One well-documented example is that of the external fertilizing teleost, the Arctic charr (Salvelinus alpinus), where individuals becoming dominant reduce sperm production and sperm swimming speed in water compared to subordinates. Here, we report how ovarian fluid differentially influences sperm velocity of dominant and subordinate male Arctic charr. That is, sperm from dominant males increase their velocity in water diluted ovarian fluid compared to that observed in water, while sperm from subordinates, on the other hand, decrease velocity in ovarian fluid compared to that observed in water. Thus, subordinates, who invest more resources in their sperm and usually show the highest sperm velocity in water, have lower gains from their investment than dominant males when sperm are swimming in ovarian fluid. In sum, our result suggests that ovarian fluid increase sperm velocity more in dominant males than in subordinate males. Although this finding could partly be caused by cryptic female choice exerted by the ovarian fluid for sperm from dominant males, an alternative and more parsimonious explanation is that sperm from dominant males may simply be better designed for swimming in ovarian fluid compared to sperm from subordinate males. Thus, sperm production in the two reproductive roles seems to be adaptively tailored to different external environments

Fugler i Norge 2000 - Rapport fra Norsk faunakomité for fugl (NFKF)

THE NORWEGIAN BIRD REPORT 2000 - a report on locally uncommon and scarce birds in Norway in 2000, by the Norwegian Bird Records Committee (NFKF)The basis of this report is the annual reports produced by the county rarities committees. For 2000 all the counties, with the exception of Finnmark and Sogn og Fjordane counties contributed to the report. Only limited information for some species was received from Troms. The Svalbard archipelago and Jan Mayen are not represented in this report. With the exception of the northernmost counties the report thus reflects fairly well the observations reported from Norway in 2000. Readers should take care to note the geographical and time delimitation of the records stated for the different species, as stated in codes immediately after the scientific name of the species. This report details records of locally uncommon and scarce birds only, and not national rarities. National rarity records are treated by the Norwegian Rare Bird Committee (NSKF) and are published separately (e.g. Mjølsnes et al. 2005). Notable observations in 2000 were influxes or higher numbers than usual of different species, such as Corncrake Crex crex, Spotted Crake Porzana porzana, Snowy Owl Nyctea scandiaca and Black Redstart Phoenicurus ochruros. New arrivals of Guillemot Uria aalge in the larger freshwater lakes in southern parts of Norway were notable. This influx follows the larger influx in 1997 from which birds still remain in these freshwater bodies. The growth of the recently established colonies of Cormorant of the subspecies sinensis continued, with 482 nests at Øra (ØF) (first confirmed breeding in 1997). The status of the colony at Orrevann (RO) in 2000 is unknown, but contained more than 100 nests in 1999 (first confirmed breeding with 6 nests in 1996). In addition many birds have been recorded from other freshwater sites in Southern Norway. The Norwegian population of Lesser White-fronted Goose (the last remaining wild population of this species in Europe) still lingers on, with 64 individuals recorded during spring migration. Breeding failure prevailed this year with only one pair with 2 juveniles recorded (compared to 17 successful breeding pairs in 1999). The partly introduced population of Barnacle Goose in the Oslofjord-area continued to increase (59 pairs in 1999). White-tailed Eagles also continued their range expansion in the southernmost regions, e.g. 5 birds recorded at Øra (ØF), where the last breeding record stems from 1882. The Peregrine also increases strongly in Norway, with now around 500 breeding pairs (up from a low of ca. 50 pairs in the 1950’s and 1960’s). The aid of playback of sound recordings has revealed more Water Rails during late autumn and winter thanhitherto known, suggesting that many birds migrate to the western coasts of Norway. The Corncrake had another good year with a new record of 131-137 individuals in 2000. The first wintering record of Common Crane from 2.1-12.3 at Jæren (RO) was notable and as with other species indicate that the climate is changing towards milder winters. Many new lekking sites of Great Snipe were also detected this year, and one unusual late record of a specimen at Østensjøvann, Ås (OA) was made 3.12. Woodcock also occurred in unusually high wintering numbers with 134 individuals. An influx of Iceland Gull was noted in the southern parts of Norway with 58 individuals, including one inland observation from Mjøsa (OP). One of the birds in Trondheim (ST) was a possible kumlieni. Readers should note that both Glaucous Gull and Iceland Gull are common and occur in larger numbers (hundreds) in the northernmost counties. An influx of Snowy Owl during the autumn was noted in all parts of the country, with 57-58 individuals. The trend towards milder winter climate has brought a significant increase in the breeding population of Grey Wagtail, and the numbers of wintering White Wagtail and Dunnock have increased. The numbers of White Wagtail subspecies yarrellii occurring during the summer months are steadily increasing. A spring influx of Stonechat brings back hope for a re-establishment of the western coast breeding population. The autumn migration of Yellow-browed Warbler resulted in a new national record in one year with 64 individuals. Also notable was a winter record of a Willow Warbler in December. Bearded Tits continued to occur in good numbers following the influx of 1999. The influx of Nutcrackers in 1995 helped establish a thriving breeding population outside their normal breeding areas in Norway (such as in ST), while the remnants of the influx of Two-barred Crossbill in 1996 finally seem to fade away. The Hawfinch is still spreading northwards and is now recorded more frequently, including as far north as TR

No Evidence for Pre-Copulatory Sexual Selection on Sperm Length in a Passerine Bird

There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection

Fugler i Norge 2003 – Rapport fras Norsk faunakomité for fugl (NFKF)

THE NORWEGIAN BIRD REPORT 2003 - a report on locally uncommon and scarce birds in Norway in 2003, by the Norwegian Bird Records Committee (NFKF) The basis of this report is the annual reports produced by the county rarities committees. All counties contributed to the report for 2003, although the Svalbard archipelago and Jan Mayen as well as Finnmark, Troms, Sogn & Fjordane and Vest-Agder counties did not publish own county reports. We believe this report reflects fairly well observations from Norway in 2003. Readers should take care to note the geographical or time delimitation of the records stated for the different species, as stated in codes immediately after the scientific name of the species. The Norwegian Bird Records Committee (NFKF) has published annual reports since 1991. The occurrence of Bewick’s Swan Cygnus columbianus was the best in NFKFs history, while the occurence of Lesser White-fronted Geese Anser erythropus at the traditional feeding and roosting site Valdakmyra, Porsanger (FI) continued to be low. One breeding pair of Pink-footed Goose Anser brachyrhynchus at Grindøya, Troms county was the first breeding attempt on the Norwegian mainland (excepting an attempt by a hybrid pair). Bar-headed Goose Anser indicus was seen in exceptionally good numbers. Gadwalls Anas strepera have occurred in steadily increasing numbers in Norway in recent years, and 2003 was the best year to date for this species. One breeding record of Smew Mergellus albellus from Vikna, Nord-Trøndelag county was the first breeding record in Norway outside Finnmark. The occurrence of Common Quail Coturnix coturnix and Corncrake Crex crex was the second best, while the occurrence of Spotted Crake Porzana porzana was the third best in NFKFs history. The Eurasian Hobby Falco subbuteo is a raptor that has occurred in high numbers in recent years, and 2003 was the best year ever. The occurrence of Avocets Recurvirostra avosetta and Black-tailed Godwits Limosa limosa was the best ever in NFKFs history, while the occurrence of migrating Broad-billed Sandpiper Limicola falcinellus was poor with only one individual during the autumn migration period. Migrating Pomarine Skuas Stercorarius pomarinus and Long-tailed Skuas Stercorarius longicaudus were seen in good numbers and the occurrence of Glaucous Gulls Larus hyperboreus was the best in NFKFs history. Also the occurrence of Little Gulls Larus minutus was very good, givingc the second best year ever. Turtle Doves Streptopelia turtur had a very good year during both spring and autumn, giving the best year in NFKFs history. The number of Hoopoes Upupa epops was the third best since 1991. The occurrences of Wood Larks Lullula arborea and Richard’s Pipits Anthus richardi was the third best, while the occurrence of Red-throated Pipits Anthus cervinus was very low. The number of Pied Wagtails Motacilla alba yarrellii, singing Grasshopper Warblers Locustella naevia, Yellow-browed Warblers Phylloscopus inornatus and Red-breasted Flycatchers Ficedula parva was the highest ever recorded, while Marsh Warbler Acrocephalus palustris, Barred Warblers Sylvia nisoria and Great Grey Shrikes Lanius excubitor experienced second best numbers since 1991. The number of Golden Oriole Oriolus oriolus was the lowest ever recorded in NFKFs history. Two-barred Crossbills Loxia leucoptera continued to occur in good numbers after the autumn 2002 influx, but very few individuals remained after the summer. The Hawfinch Coccothraustes coccothraustes still show a marked increase in the north of its distribution range, especially in the Trøndelag counties. The Ortolan Bunting Emberiza hortulana continued to occur in low numbers while the occurrence of Little Buntings Emberiza pusilla was the second best in NFKFs history

Resident bird species track inter-annual variation in spring phenology better than long-distance migrants in a subalpine habitat

The ability to track variation in climate is important for species to persist in a given environment. Lack of responses to both long-term changes and inter-annual variation in climate parameters can result in reduced fitness and population decline. Furthermore, migration strategy can influence the ability to track climatic variation due to the potential to use reliable environmental cues. Here, we studied the temporal relationship between birch leafing and onset of breeding for three bird species with contrasting migration strategies over a 20-year period in a subalpine habitat in Central Norway. We found no temporal change in birch leafing date or breeding onset for the three bird species over the study period. However, we found a statistically significant difference in the ability to track inter-annual variation in birch leafing date between the resident and two long-distance migratory species. The resident great tit Parus major was more capable of initiating egg laying in closer association to variation in birch leafing in early springs, than the long-distance migratory European pied flycatcher Ficedula hypoleuca and common redstart Phoenicurus phoenicurus. Long-distance migrants seem to have been constrained by arrival date or time from arrival to entering the breeding areas, in contrast to resident birds, which might be better able track early initiation of spring in breeding areas by adjusting egg laying date. Our findings highlight the importance of not solely studying directional long-term climatic change, but also pay attention to inter-annual variation