Is the Subject Area "Sperm" applicable to this article? Yes On this Wikipedia the language links are at the top of the page across from the article title. Perhaps the key driver for increased motility, however, is sperm competition between the ejaculates of different males. Of course, it is also possible that sperm are simply forced to group by the male, which would mean that any sperm altruism is illusory in the sense that it did not evolve through natural selection acting at the level of sperm (sperm lack evolutionary agency). Environmental ranges Depth range (m): 0 - 662.5 Or is it? WebFusitriton oregonensis (Redfield, 1848) Oregon triton Native range | All suitable habitat | Point map | Year 2100 This map was computer-generated and has not yet been reviewed. The filiform spermatozoon of Littorina contains a conical acrosome positioned anteriorly to the nucleus, a series of pores that connect the mitochondria directly with the external environment, and a distinct joint separates the mitochondrial and tail regions. Reproduction: Each triton is one gender. Veliger larvae of the NE Pacific snail Fusitriton oregonensis were reared in culture for 4.5 to 4.6 years from hatching to metamorphosis and through postlarval growth to reproduction. Late veligers grew slowly, but shell sizes increased even in the 4th and 5th years. (A) Sperm's perspective (population is at the scale of the female). Parasperm may also actively release compounds that harm eusperm: immature lancet paraspermatids are known to produce digestive enzymes that may end up being released in the female [19]. WebThe mechanisms by which Cnemidocarpa finmarkiensis persists in the presence of F. oregonensis is unknown. As we have seen, sperm can benefit from joining forces with others, helping their kin, or even harming others. This is nowhere more important than in the measure of genetic relatedness. The ability of sperm to express their own genes suggests that we should not view them simply as passive automata that serve the male, but rather as semi-independent agents with their own evolutionary interests. One interpretation is that these sperm are simply developmental failures, but their sheer numbers, more than half of the sperm of an ejaculate in some cases, suggest otherwise [2]. [9] https://doi.org/10.1371/journal.pbio.0060130.g003. (urn:lsid:marinespecies.org:taxname:476496), The webpage text is licensed under a Creative Commons Attribution 4.0 License, (urn:lsid:marinespecies.org:taxname:476496). However, there is also evidence for gene expression in sperm during and after meiosis [35,36], including the striking examples of segregation distorters. Its range extends from the Bering Sea to northern Mexico; it is also found on coastlines in The nature of starfish This is fixed, however, by shifting scales. WebFusitriton oregonensis is a species of large predatory sea snail, a marine gastropod mollusk in the family Cymatiidae. Annotated list of shell-bearing gastropods
And while no speed advantage in grouping was found in the house mouse, Mus musculus [10], sperm groups swim faster than single sperm in the Norway rat [10] and the wood mouse, Apodemus sylvaticus (discussed below) [3]. Hundreds of sperm agglutinate by the head in the fishfly, Parachauliodes japonicus, and swim into the female spermatheca to the tune of a synchronised tail-beat, which propels them faster in large groups than in small [9]. The eggs are placed in rectangular capsules in a spiral pattern. When this happens near the egg, the acrosome reaction promotes fertilisation, but a premature reaction leaves sperm impotent and useless by the time they reach the egg. After mating the female tritons lay the eggs on vertical surfaces and under rock ledges. This might occur either through direct recognition of the same genotypes in other sperm [15,16], or more simply through a proxy that allows joining with same-male rather than foreign sperm. Beu, A. (2007). WebFusitron oregonensis (Redfield, 1848) Common name(s): Hairy triton, Oregon hairy triton: Synonyms: Argobuccinium oregonense: Phylum Mollusca Class Gastropoda Subclass Prosobranchia Order Mesogastropoda Suborder Taenioglossa Family Cymatiidae: Fusitron oregonensis from 15 m depth, Sares Head. Fusitriton is a genus of large predatory sea snails marine gastropod molluscs in the family Cymatiidae. WebFusitron oregonensis (Redfield, 1848) Common name(s): Hairy triton, Oregon hairy triton: Synonyms: Argobuccinium oregonense: Phylum Mollusca Class Gastropoda Subclass Prosobranchia Order Mesogastropoda Suborder Taenioglossa Family Cymatiidae: Fusitron oregonensis from 15 m depth, Sares Head. Water temperature and chemistry ranges based on 50 samples. WebThe prosobranch Fusitriton oregonensis exhibits an unusual form of sperm polymorphism, which is attached in groups of about fifty to worm-shaped, apyrene, carrier sperm, and the possible functions of the lancet and carrier sperm are discussed. Sperm of the short-beaked echidna, Tachyglossus aculeatus, also form large groups of up to 100 in which coiled sperm heads are stacked tightly and cemented together, which again improves swimming speed [11]. Calculations of relatedness require one to assign the relevant population scale at which individuals interact and compete (see Box 1, [16]). The morphology of the slender, filiform spermatozoa of 13Protodrilus species of 22 different populations is investigated by light and transmission electron microscopy and elucidates possible plesiomorphous and apomorphous sperm traits. This is a rare occurrence because queens brutally fight until one is dead. here. But do sperm preferentially group with others from the same male, and moreover, is there evidence for sperm altruism? Similarly, carabid beetle species with more complex male genitalia and longer periods of mate guarding, characteristics typical of species with a high risk of inter-male sperm competition, tend to have relatively large sperm bundles, suggesting that sperm competition promotes the evolution of larger sperm groups [14]. It is in the interests of each individual sperm to rise to the challenge and do anything to fertilise an egg. What is clear is that the spermmale partnership can be an uneasy one, steeped in potential conflicts. And, importantly, we are taking a different scale for the male and the sperm here: we assume that all evolutionary competition for sperm occurs within the female: she is the population for each sperm (Box 1). Apyrene sperm are parasperm that lack DNA altogether, which makes them simply an accessory of the male, as is the case for seminal fluids. Human sperm were famously suggested to be heteromorphic, comprising one type that contributed to fertilisation and another, the kamikaze sperm, that sacrificed its own chances of fertilisation to neutralise the sperm of competing ejaculates, for example by blocking, incapacitating, or killing rival sperm [28]. The Bulletin of the Russian Far East Malacological Society 15-16: 5-30. WebThe prosobranch Fusitriton oregonensis exhibits an unusual form of sperm polymorphism, which is attached in groups of about fifty to worm-shaped, apyrene, carrier sperm, and the possible functions of the lancet and carrier sperm are discussed. This study was not planned as one of larval longevity and replication is low, but the observations are surprising and noteworthy. WebFusitron oregonensis (Redfield, 1848) Common name(s): Hairy triton, Oregon hairy triton: Synonyms: Argobuccinium oregonense: Phylum Mollusca Class Gastropoda Subclass Prosobranchia Order Mesogastropoda Suborder Taenioglossa Family Cymatiidae: Fusitron oregonensis from 15 m depth, Sares Head. In 1989, the Oregon hairy triton was declared the states official sea shell by the sixty-fifth Legislative Assembly of Oregon. Gulbin, V. V.; Chaban, E. M. (2012). The U-shaped outer layer of each mitochondrial element has been reported here in the subfamily Odontocimbiolinae and may prove to be a diagnostic feature of the Volutidae family. Radulae of Three Gastropodous Species from the Sagami Bay, which were Collected by The Emperor Showa. [1] For faster navigation, this Iframe is preloading the Wikiwand page for Fusitriton oregonensis . WebThe Oregon triton is a common subtidal species of marine snail found from southern Califor-nia to the Gulf of Alaska and to the eastern Bering Sea. Total length 13 cm. https://doi.org/10.1371/journal.pbio.0060130.g001. Conversely, sperm sociality represents fertilebut so far little exploredground for the study of social evolution. There is a second apyrene sperm, which is lancet-shaped and has a different internal organization than the carrier, but does not transport eupyrene sperm.The eupyrene sperm are filiform (185 m long), with a conical acrosome, elongate nucleus and midpiece. This service is powered by LifeWatch Belgium, https://www.biodiversitylibrary.org/page/3370106, http://rfems.dvo.ru/images/rfems/bulletin/vol_015_016/article_01.pdf, http://www.biolbull.org/content/213/2/152.full.pdf+html, http://ashipunov.info/shipunov/school/books/golikov1978_rakov_brjukh_litorali_morei_sssr.djvu, To Biodiversity Heritage Library (1 publication), To Biodiversity Heritage Library (25 publications), To Biological Information System for Marine Life (BISMaL), To USNM Invertebrate Zoology Mollusca Collection. It occurs occasionally intertidally and is com-mon to 140 fm on rock, sand, shell, or gravel sub-strate. https://doi.org/10.1371/journal.pbio.0060130.g002. (B) Montage of side-by-side transmission electron microscopy sections of the carrier (i) and lancet (ii) parasperm. WebDepth range based on 90 specimens in 1 taxon. Show More The snail was given its specific name oregonensis (meaning "of Oregon") to honor the Oregon Territory by conchologist John Howard Redfield in 1846. KRF is supported by National Institute of General Medical Sciences Center of Excellence Grant 5P50 GM 068763-01. But in other species, there may be a case for spitefully suicidal sperm. Little is known of the snail's feeding habits, but they are believed to feed on other mollusks,[6] ascidians ("sea squirts"),[8] and more rarely, sea urchins. Only five of the 14 species of solitary ascidians in the San Juan Islands, Washington, USA commonly co-occur with an abundant predator of the rocky subtida But what would altruism look like in these groups? More spectacularly social sperm are found in the humble Norway rat, Rattus norvegicus, and several other murid rodents, which have sperm with a distinctive hook-shaped head (Figure 2). What may be going on is a life-or-death lottery that carries extremely good odds. They contain large stores of glycogen in. A comparable effect is seen in the opossum. (D) Electron microscopy of exquisite sperm head alignment in conjugate sperm pair (credit: Harry Moore). https://doi.org/10.1371/journal.pbio.0060130.t001. Strathmann M.F., Strathmann R.R. Zeitschrift fr Zellforschung und Mikroskopische Anatomie. Yes WebAbstract. No drawings available for Cymatiidae. He has little to gain from sperm infighting, and instead only seeks to ensure that all of the eggs available are fertilised by his sperm. The shells often wash up on the coast during high tides.[2][3]. Evidence supports the conclusion of Healy (1988b) that Vermetoidea are not closely related to lower caenogastropods, such as Cerithioidea and related groups and for the first time, nuclear degradation in parasperm of VermetOidea is shown to progress by an apoptotic mechanism. The viable, eupyrene sperm are attached in groups of about fifty to worm-shaped, apyrene, carrier sperm. Part I. While subsequent studies did not support this idea in humans [31,32], similar mechanisms might occur in some snails. For example, if there are two alleles at equal frequency in the population at a focal locus, then unrelated people will have probability of having the same allele at that locus. Biological Bulletin. 213(2) 152-159. Unsolved Mystery Beu A.G. 2010 [August]. Sperm heteromorphism: The analogy with an insect worker caste appears to go even further in species with morphologically distinct sperm types, a phenomenon known as sperm heteromorphism. WebThese patterns of abundance correlate with feeding preferences and distributional patterns of the predatory snail Fusitriton oregonensis, which occurs only in rocky subtidal sites, prefers ascidians over other invertebrates as prey and prefers phlebobranchs over stolidobranchs. https://en.wikipedia.org/w/index.php?title=Fusitriton&oldid=1010071512, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 3 March 2021, at 17:24. The Ocean Biogeographic Information System (OBIS). The potential for sperm to have a social life then seems clear, but does this help us to make sense of the diverse sperm behaviour seen in nature? It is said that the species name (oregonesis) celebrated the naming of the Oregon territory. No drawings available for Cymatiidae. If sperm are all equally likely to be crippled, and pairing more than doubles their chances of fertilisation, it is in each sperm's personal fitness interest to buy a ticket [15]. WebThe Oregon triton inhabits the intertidal and subtidal to 90 m deep, and is more commonly found on rocky substrates. And, developmentally, are sperm able to influence whether they become a parasperm or a eusperm? No, Is the Subject Area "Sperm head" applicable to this article? No, Is the Subject Area "Ova" applicable to this article? WebThese patterns of abundance correlate with feeding preferences and distributional patterns of the predatory snail Fusitriton oregonensis, which occurs only in rocky subtidal sites, prefers ascidians over other invertebrates as prey and prefers phlebobranchs over stolidobranchs. TP is supported by a grant from the Natural Environment Research Council. VENUS (The Japanese Journals of Malacology). 50(4) 302304. The queens are now less rather than more likely than chance (relative to the local frequency) to have the alleles in common with the other: the two queens are in fact negatively related [25,43]. Show More The snail was given its specific name oregonensis (meaning "of Oregon") to honor the Oregon Territory by conchologist John Howard Redfield in 1846. [1], The snail was given its specific name oregonensis (meaning "of Oregon") to honor the Oregon Territory by conchologist John Howard Redfield in 1846. WebFusitriton oregonensis (Oregon hairy triton) is a species of large predatory sea snail, a marine gastropod mollusk in the family Cymatiidae. From [10]. Reproduction: Each triton is one gender. Insects such as the cowpea beetle, Callosobruchus maculatus, inseminate more sperm than the female can actually store [30]. Larval shells grew in length from 0.20 to 3.9 mm. If a female mates once, all sperm have the same probability of sharing genes, and relatedness at the scale of the female is zero. WebFusitriton is a genus of large predatory sea snails marine gastropod molluscs in the family Cymatiidae. This study was not planned as one of larval longevity and replication is low, but the observations are surprising and noteworthy. These social sperm are often highly adapted to the task. Veliger larvae of the NE Pacific snail Fusitriton oregonensis were reared in culture for 4.5 to 4.6 years from hatching to metamorphosis and through postlarval growth to reproduction. WebFusitriton oregonensis (Redfield, 1846) AphiaID 476496 (urn:lsid:marinespecies.org:taxname:476496) Classification Biota Animalia (Kingdom) Mollusca (Phylum) Gastropoda (Class) Caenogastropoda (Subclass) Littorinimorpha (Order) Tonnoidea (Superfamily) Cymatiidae (Family) Fusitriton (Genus) Fusitriton oregonensis WebFusitriton oregonensis (Redfield, 1848) Oregon triton Native range | All suitable habitat | Point map | Year 2100 This map was computer-generated and has not yet been reviewed. Phylogenetic studies suggest that sperm competition may be associated with the evolution of heterospermy in some taxa [22], but not in others [23]. But like all partnerships, they will perform the best in the face of their worst foe: the sperm of another male that threatens to eradicate their genetic trace altogether. In the case of sperm in internally fertilising species, we expect the majority of competition among sperm to function within the female, and we therefore use the single female as the population measure p in Figure 1. The charming great-diving beetle Dytiscus marginalis has sperm with a distinctive flat side that allows some sperm to pair upstuck together by the headand use both tails to propel themselves onward [8]. Pers. Water temperature and chemistry ranges based on 50 samples. In order to fuse with an egg, mammalian sperm must undergo an acrosome reaction, in which their acrosome tip is bared of its membrane and sperm hydrolytic enzymes are released. As in eusocial insects [17], therefore, a combination of kinship and coercion may work in concert to produce sperm sociality. For example, the Oregon triton, Fusitriton oregonensis, has two distinct parasperm types: sperm shuttlers (above) and lancets (Figure 4A4C), and experiments that add a homogenate of parasperm to eusperm find that this causes the eusperm to clump together in vitro, an effect not seen when adding eusperm to eusperm [19]. Habe, T. (1992). (A) Immature Oregon triton (Fusitriton oregonensis) lancet parasperm seen with scanning electron microscopy, showing the tail brush still present, which later develops into part of the body of the parasperm. [5], The Oregon hairy triton is native to the northwestern coast of North America. The dimorphic spermatozoa in Strombus were first described by Brock in I887 in the case of S. Lentiginosus and his description and figures are sufficient to show how marked and striking is the dimorphism existing here and it is surprising that this has not been made the subject of further investigation by more recent workers. The answer is simple: only one is needed to head the colony, and natural selection favours fighting to be the one that does. In some extreme cases, however, we already know the answer. In this case, there can be no malesperm conflict, and sperm evolution is driven by the male alone. View 4 excerpts, references background and results. Duggins, personal observation) can consume urchins, but the crabs and eels are rare in this benthic community, and Fusitriton, while common, eats urchins rarely (D. 0. It occurs occasionally intertidally and is com-mon to 140 fm on rock, sand, shell, or gravel sub-strate. A male and female have just mated; what would one predict? And all else being equal, selection for altruistic grouping behaviours will increase with increased levels of mixing with the sperm of other males, which offers an alternative explanation for the observed link between inter-male sperm competition and grouping (purple line, Figure 1A). PLoS Biol 6(5): WebFusitriton is a genus of large predatory sea snails marine gastropod molluscs in the family Cymatiidae. Copyright: 2008 Pizzari and Foster. Can you list the top facts and stats about Fusitriton oregonensis? [ .., .. With these questions, we return to the paradox of those sperm that cannot, or will not, fertilise an egg. The two males are in strong conflict with one another as their ejaculates compete to fertilise the eggs, an inter-male process called sperm competition. WebFusitriton oregonensis, which has a reported range from California to northern Japan (Beu, 1978) that includes the isolated seamounts Cobb and Patton (Birkeland, 1971; Somerton, 1981). Typically, chance is taken relative to the population frequency of the relevant alleles. This may mean temporary alliances with other sperm, but may also mean strong competition among the sperm of the same ejaculate. [1], Species within the genus Fusitroton include:[1]. [1] The snail was given its specific name oregonensis (meaning "of Oregon") to honor the Oregon Territory by conchologist John Howard Redfield in 1846. For example, male butterflies produce two types of sperm: eupyrene and apyrene sperm. Total length 13 cm. of Commander Islands. [5]. (C) Apical hook morphology across different species of rodents (1, Bunomys fratrorum; 2, M. musculus; 3, R. norvegicus; 4, Dasymys incomtus; 5, Pseudomys oralis; 6, Maxomys surifer; 7, Melomys burtoni; 8, A. sylvaticus; 9, A. speciosus). If the actions of sperm were to harm the female, there would also be competition among sperm in different females, which would change the relatedness values and, perhaps, evolutionary predictions [44]. Yes When two individuals share more genes in common than the population average, they are genetically related, and natural selection can favour altruistic behaviours that invest in another's reproduction, as with social insect workers. Transcriptomic and mutant studies of sperm will help to reveal their potential to act autonomously and affect one another in an ejaculate, particularly when applied to different sperm haplotypes produced by heterozygous males [37]. It is fairly common, and can be locally abundant. But now our female mates with a second male, and the battlegrounds shift somewhat. At the extremes, sperm could be kept entirely separate or mix fully. The shells grow from 8 to 13 centimetres (3 to 5in) long. This situation can favour altruism, and indeed, as the sperm of our focal male become rarer, altruism becomes a better option than spite (it is more difficult to knock-down a majority than support a minority). In support of this theory, recent artificial insemination experiments in the silkworm moth Bombyx mori revealed that parasperm may facilitate transport of eusperm to the site of sperm storage and/or fertilisation [18], and the enormous size of the parasperm in some molluscs, up to 140 times larger than eusperm, may also help to shuttle eusperm to the eggs [19]. (1846). Redfield J.H. 476496 (For example, taking a focal rare allele in a heterozygous queen, the focal individual frequency (pA) is 0.5, average frequency in the other queen (pR) is about 0.125 ( chance she is also heterozygous), and local frequency (p) is the average of the frequency in each, or 0.3125, giving r = (0.125 0.3125)/(0.5 0.3125) = 1). (A) Immature Oregon triton (Fusitriton oregonensis) lancet parasperm seen with scanning electron microscopy, showing the tail brush still present, which later develops into part of the body of the parasperm. An extraordinarily long larval duration of 4.5 Years from hatching to metamorphosis for teleplanic veligers of Fusitriton oregonensis. Only five of the 14 species of solitary ascidians in the San Juan Islands, Washington, USA commonly co-occur with an abundant predator of the rocky subtida (B) Male perspective (population is at the scale of the real population). As opossum conjugate sperm pairs move through the female oviduct and approach the egg, they split up, and while one swims on with fervour, the other falls away and loses motility [12,13]. After mating the female tritons lay the eggs on vertical surfaces and under rock ledges. Duggins, personal observation). In other molluscs (e.g., Aporrhais pespelecanis), parasperm morphology suggests that they deliver nutrients either to eusperm or to the female [19], which is likely, either directly or indirectly via the female, to increase eusperm fitness. Sperm evolution requires one to consider Darwinian selection on multiple interacting parties and at multiple levels, and this lends itself to the tools of sociobiology: kin selection and multi-level selection theory [4]. It is said that the species name (oregonesis) celebrated the naming of the Oregon territory. The nucleus of the parasperm is eliminated during paraspermiogenesis, but there is considerable post-transcriptional secretion activity resulting in the production of a variety of granules, some rich in glycoproteins. Typically, only one sperm type (eusperm) is involved in fertilisation, while the other type(s) (parasperm) do not or cannot fertilise the egg. Puzzling at first, this hook is now thought to help sperm to reversibly form groups of up to several hundred sperm (Figure 2A and 2B). Total length 13 cm. (A) Paired and single sperm of the short-tailed opossum Monodelphis domestica. Yes WebGenus Fusitriton Species oregonensis Common Name: Hairy Oregon Triton. comm. This is not yet clear. Some examples are better interpreted in terms of selfishness by the male, such as sperm flushing. Taking two competing queens as an example, we can recalculate relatedness using the formula: r = (pR - p)/(pA - p) but where p (the population frequency) is no longer the frequency of the focal allele in the whole population of bees, but the average frequency in the two queens (local frequency). That is, are the actor and recipient genetically related? Our simple relatedness calculations assume that sperm social behaviours have no negative effects on females or on the probability that eggs are left unfertilised (Figure 1, Box 1). As for all assessments, assessments made in sociobiology must be tied to a specific reference scale, be it a local group or a global community [41,42]. Apyrene sperm in the green-veined butterfly, Pieris napi, have been shown to reduce the probability that a female will re-mate with another male [24]. No, Is the Subject Area "Altruistic behavior" applicable to this article? Examination of the ultrastructure of the mature spermatozoa of three species of Monacha in Egypt revealed that sperm of each of them composed of head, neck region, midpiece and end-piece, which recommend that they are actually three valid species representing this genus of land snails in Egypt. The question of sperm autonomy lies in the relative degree to which sperm can express their genes when in the haploid state. Later features, including the peripheral condensation of nuclear chromatin followed by nuclear invagination, the posterior breakdown into nuclear vesicles (caryomerites), centriole multiplication and the synthesis of secretory products, are the most conspicuous changes in the process of paraspermatogenesis. Intergovernmental Oceanographic Commission (IOC) of UNESCO. The prosobranch Fusitriton oregonensis exhibits an unusual form of sperm polymorphism. The incentive for producing apyrene sperm, however, appears still to result from evolutionary conflict; in this case with other males. The secret to unravelling the mystery of subfertile and infertile sperm may lie in understanding their social lives. This opportunity paves the way, in evolutionary terms, for behaviours that reduce an individual sperm's chance of fertilising in order to increase the chances of another: sperm altruism. Moreover, choosing the appropriate scale can help to capture the relevant biology. There is another interpretation that puts the sperm back in the spotlight: perhaps sperm are able to specifically target and group together with their closest relatives. Features not previously reported in other ultrastructural studies of paraspermatozoa include the acrosome-like structure of the head, the structure ofthe midpiece zone, the glycogen sheath of the major tail, the dense annular structure at the junction of the midpiece and major tail and the presence of microtubules in the final phase of head and midpiece maturation. The development of, View 3 excerpts, references background and results, By clicking accept or continuing to use the site, you agree to the terms outlined in our. Fusitriton oregonensis AquaMaps Data sources: GBIF OBIS Upload your photos Google image | No photo available for this species. Journal of the Marine Biological Association of the United Kingdom. Appreciating this sociality is a promising step forward in unravelling the mystery of subfertile or sterile sperm. Segregation distorters are groups of linked genes that are able to prevent the proper development of sperm that lack them [3739], such that in a heterozygote male, one half of the sperm will eliminate the other half. Show More The snail was given its specific name oregonensis (meaning "of Oregon") to honor the Oregon Territory by conchologist John Howard Redfield in 1846. Microtubules are found outside the nucleus and mitochondria during the final stages of spermiogenesis, when elongation is almost complete, and it is suggested that as the Golgi body migrates around the nucleus the endoplasmic reticulum may circulate with it. Take the opossum pairing. In order to make social evolution predictions, relatedness should always be measured at the locus or loci in the genome that drive the social action of interest (average across-genome measures are only a proxy for the loci that drive a behaviour). WebFusitriton oregonensis (Oregon hairy triton) is a species of large predatory sea snail, a marine gastropod mollusk in the family Cymatiidae. The viable, eupyrene sperm are attached in groups of about fifty to worm-shaped, apyrene, carrier sperm. Late veligers grew slowly, but shell sizes increased even in the 4th and 5th years. Are these effects due to natural selection acting on the male or on the individual sperm? Where there is the potential for altruistically helping close relatives, the potential to spitefully harm others naturally follows. A more malicious and mysterious social behaviour is spite, whereby an actor reduces their personal fitness to harm a recipient [25]. Sperm features suggest a close relationship between T. amurula and M. tuberculata and more broadly with other 'Group T cerithioidean families exhibiting four equal-sized eusperm mitochondria, including Potamididae, Modulidae, Scaliolidae, Melanopsidae, Semisulcospiridae and Pleuroceridae. Why it is good to swim more quickly? But why would close relatives kill each other? Conflict between sperm and male genomes may often be more subtle, and understanding its full scope and effects will benefit from a number of complementary approaches.