scholarly journals Sexual conflict in self-fertile hermaphrodites: reproductive differences among species, and between individuals versus cohorts, in the leech genus Helobdella (Lophotrochozoa; Annelida; Clitellata; Hirudinida; Glossiphoniidae)

2018 ◽  
Author(s):  
Roshni G. Iyer ◽  
D. Valle Rogers ◽  
Christopher J. Winchell ◽  
David A. Weisblat
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Life Histories ◽  
Reproductive Capacity ◽  
Reproductive Parameters ◽  
Male And Female ◽  
The Third ◽  
Reproductive Life ◽  
Self Fertilization ◽  
Cross Fertilization

ABSTRACTLeeches and oligochaetes comprise a monophyletic group of annelids, the Clitellata, whose reproduction is characterized by simultaneous hermaphroditism. While most clitellate species reproduce by cross-fertilization, self-fertilization has been described within the speciose genus Helobdella. Here we document the reproductive life histories and reproductive capacities for three other Helobdella species. Under laboratory conditions, both H. robusta and H. octatestisaca exhibit uniparental reproduction, apparently reflecting self-fertility, and suggesting that this trait is ancestral for the genus. However, the third species, H. austinensis, seems incapable of reproduction by self-fertilization, so we inferred its reproductive life history by analyzing reproduction in breeding cohorts. Comparing the reproductive parameters for H. robusta reproducing in isolation and in cohorts revealed that reproduction in cohorts is dramatically delayed with respect to that of isolated individuals, and that cohorts of leeches coordinate their cocoon deposition in a manner that is not predicted from the reproductive parameters of individuals reproducing in isolation. Finally, our comparisons of reproductive capacity for individuals versus cohorts for H. robusta, and between different sizes of cohorts for H. austinensis, reveal differences in resource allocation between male and female reproductive roles that are consistent with evolutionary theory.

The life histories of north-temperate populations of the crayfish Cambarus robustus and Cambarus bartoni

1985 ◽  
Vol 63 (10) ◽  
pp. 2313-2322 ◽  
Author(s):  
Premysl Hamr ◽  
Michael Berrill
Keyword(s):  
Life History ◽  
Life Histories ◽  
Carapace Length ◽  
Late Summer ◽  
Temperate Climate ◽  
Free Living ◽  
Southern Ontario ◽  
The Third ◽  
Early Fall ◽  
First Time

The life histories of the crayfish Cambarus robustus and Cambarus bartoni were studied in the Kawartha Lakes region of southern Ontario. There were marked differences in their breeding and molting cycles compared with the familiar pattern of the Orconectes species of this region. Egg extrusion occurred later (July in C. robustus, June in C. bartoni), and juveniles therefore did not become free living until late summer or early fall. With little growing time in their first summer, they measured only 5–10 mm in carapace length (CPL) before growth ceased for the winter. At the end of their second summer the still immature crayfish measured 17–26 mm CPL in C. robustus and 13–20 mm CPL in C. bartoni. Maturity was therefore not attained until the end of the third summer, when most C. robustus matured at 34–45 mm CPL and C. bartoni at 25–30 mm CPL. The majority of individuals apparently reproduced for the first time during their fourth summer; a few apparently survived into another summer, reaching carapace lengths greater than 50 mm in C. robustus and 30 mm in C. bartoni. In males of both species, form 1 and form 2 occur throughout the summer. Although lacking the synchrony of Orconectes species, breeding and molting activities are still confined to the period between April and October. The timing of the life-history events observed in these two Cambarus species may be adaptations to seasonal stresses of the swift water environments that these species inhabit as well as to the relative harshness of the northern temperate climate.

Genetics of Gracilaria sp. (Rhodophyceae, Gigartinales). IV. Mitotic recombination and its relationship to mixed phases in the life history

1977 ◽  
Vol 55 (22) ◽  
pp. 2810-2817 ◽  
Author(s):  
John P. van der Meer ◽  
Edna R. Todd
Keyword(s):  
Life History ◽  
Red Algae ◽  
Chromosome Numbers ◽  
Life Histories ◽  
Mitotic Recombination ◽  
Male And Female ◽  
Genetic Techniques ◽  
Standing Problem ◽  
Plant Colour

The long-standing problem of mixed phases in life histories of red algae was investigated by genetic techniques. Diploid tetrasporophytes of Gracilaria sp. growing in culture produced functional male and female gametangia in addition to tetraspores. Sporelings resulting from fertilizations involving these gametangia were polyploid, their chromosome numbers indicating that gametes from the tetrasporophyte were diploid. The tetrasporophytes themselves were heterozygous for two genes affecting plant colour. These markers were observed to become homozygous in twin spots of recombinant tissue at the same time that gametangia were formed. All the observations are consistent with the interpretation that both gametangia and recombinant twin spots arise as a consequence of mitotic recombination. The broader implications of these observations for the Rhodophyceae are discussed.

scholarly journals Foundress Number, But Not Queen Size or Boldness, Predicts Colony Life-History in Wild Paper Wasps

2019 ◽  
Author(s):  
Colin M. Wright ◽  
David N. Fisher ◽  
Wayne V. Nerone ◽  
James L.L. Lichtenstein ◽  
Elizabeth A. Tibbetts ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Traits ◽  
Positive Association ◽  
Paper Wasps ◽  
Trade Offs ◽  
Behavioral Tendencies ◽  
Queen Size

AbstractColonies of social insects exhibit a spectacular variety of life histories. Here we documented the degree of variation in colony life-history traits, mostly related to productivity, in two species of wild paper wasps. We then tested for associations between colony life-history traits to look for trade-offs or positively associated syndromes, and examined whether individual differences in the behavioral tendencies of foundresses (Polistes metricus) or the number of cofoundresses (P. fuscatus) influenced colony life-history. The majority of our measures of colony life-history were positively related, indicating no obvious resource allocation trade-offs. Instead, the positive association of traits into a productivity syndrome appears to be driven by differences in queen or microhabitat quality. Syndrome structure differed only marginally between species. Queen boldness and body size were not associated with colony life-history inP. metricus. Colonies initiated by multipleP. fuscatusfoundresses were generally more productive, and this advantage was approximately proportional to the number of cofoundresses. These findings demonstrate that colony life-history traits can be associated together much like individual life-history traits, and the associations seen here convey that differences in overall productivity drive between-colony differences in life-history.

A Comparision of Reproduction and Longevity in Pyrethroid-Resistant and Susceptible German Cockroach (Blattodea: Blattellidae) Field-Collected Strains

1991 ◽  
Vol 26 (4) ◽  
pp. 408-418 ◽  
Author(s):  
Mary H. Ross
Keyword(s):  
Life History ◽  
Resistant Strain ◽  
Life Histories ◽  
Strain Differences ◽  
German Cockroach ◽  
The Third ◽  
Significant Difference ◽  
Resistant Strains ◽  
Egg Case ◽  
Cockroach Blattella Germanica

Life histories of five field-collected strains of the German cockroach, Blattella germanica, were studied. Three were highly resistant to pyrethrins and allethrin; two were susceptible. Life history parameters of the susceptible strains and one of the resistant strains were closely similar. Two of the three resistant strains differed from the susceptible strains and from the third resistant strain. Differences from the latter strains included a longer interval between hatch of successive egg cases, fewer viable (hatched) egg cases per female, a more uneven pattern of maturation among nymphs from individual oothecae (egg cases), fewer adult progeny per egg case, and lower total numbers of adult progeny per life span of females. No significant difference occurred between the two resistant strains in any of the foregoing characteristics.

scholarly journals Life in the Slow Lane: Reproductive Life History of the White-Browed Scrubwren, an Australian Endemic

The Auk ◽  
2000 ◽  
Vol 117 (2) ◽  
pp. 479-489 ◽  
Author(s):  
Robert D. Magrath ◽  
Ashley W. Leedman ◽  
Janet L. Gardner ◽  
Anthony Giannasca ◽  
Anjeli C. Nathan ◽  
...  
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Life History Strategy ◽  
Breeding Biology ◽  
Long Period ◽  
Successful Attempt ◽  
Reproductive Life ◽  
History Of ◽  
Small Clutch

Abstract An understanding of geographic and phylogenetic variation in passerine life histories is hampered by the scarcity of studies from the Southern Hemisphere. We documented the breeding biology of the White-browed Scrubwren (Sericornis frontalis), an Australia endemic in the Pardalotidae (parvorder Corvida). Like other members of the Pardalotidae, scrubwrens had a long laying interval (two days), a long incubation period (declining from 21 to 17 days through the season), and a long period of postfledging parental care (6 to 7 weeks). Scrubwrens appeared to be typical of the Australian Corvida in having a small clutch size (three eggs) and a long breeding season (5.4 months), and they also had a long interval between breeding attempts (10 days after a failed attempt, 21 days after a successful attempt). Scrubwrens were multibrooded, often raising two broods successfully and occasionally raising three broods. The breeding biology of scrubwrens adds further support to claims of a distinct life-history strategy for members of the Corvida but also reinforces evidence that some “Corvida” life-history traits more specifically are those of the Pardalotidae.

An approach to describing ecosystem performance ``through the eyes of salmon''

1997 ◽  
Vol 54 (12) ◽  
pp. 2964-2973 ◽  
Author(s):  
Lars E Mobrand ◽  
James A Lichatowich ◽  
Lawrence C Lestelle ◽  
Thomas S Vogel
Keyword(s):  
Life History ◽  
Watershed Management ◽  
Performance Measures ◽  
Life Histories ◽  
Space Structure ◽  
Specific Information ◽  
The Third ◽  
Pass Through ◽  
And Performance ◽  
Watershed Health

The intent of this paper is to show that discussion of watershed health and salmon (Oncorhynchus sp.) performance can incorporate a much greater degree of complexity without loss of clarity. We can and should include more temporal-spatial detail, more life history complexity, and more watershed-specific information. The framework and performance measures used in watershed management generally, and salmon management specifically, are inadequate. The bottleneck metaphor is cited all too frequently as a basis for discussion. The bottleneck analogy is useful in understanding capacity, but capacity alone cannot explain observed responses of salmon populations to environmental change. An argument can be made that where protection and enhancement of weak stocks is the priority, productivity is a more critical variable. However, a framework built only around productivity and capacity is also not sufficient. It neglects the need for connectivity of habitats that salmon must pass through to complete their life histories. Adding life history diversity as the third component of performance provides the time and space structure needed to deal with connectivity while also allowing for integration of populations where they mingle.

scholarly journals Telomeres positively correlate with pace-of-life and elongate with age in a wild mammal

2021 ◽  
Author(s):  
Mathilde Tissier ◽  
Patrick Bergeron ◽  
Dany Garant ◽  
Sandrine Zahn ◽  
Francois Criscuolo ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Life Histories ◽  
Life History Strategies ◽  
Trade Off ◽  
Pace Of Life ◽  
Trade Offs ◽  
Proactive Behaviour ◽  
Anti Cancer ◽  
Fast Pace

Understanding ageing and the diversity of life histories is a cornerstone in biology. Telomeres, the protecting caps of chromosomes, are thought to be involved in ageing, cancer risks and to modulate life-history strategies. They shorten with cell division and age in somatic tissues of most species, possibly limiting lifespan. The resource allocation trade-off hypothesis predicts that short telomeres have thus co-evolved with early reproduction, proactive behaviour and reduced lifespan, i.e. a fast Pace-of-Life Syndrome (POLS). Conversely, since short telomeres may also reduce the risks of cancer, the anti-cancer hypothesis advances that they should be associated with slow POLS. Conclusion on which hypothesis best supports the role of telomeres as mediators of life-history strategies is hampered by a lack of study on wild short-lived vertebrates, apart from birds. Using seven years of data on wild Eastern chipmunks Tamias striatus, we highlighted that telomeres elongate with age and do not limit lifespan in this species. Furthermore, short telomeres correlated with a slow POLS in a sex-specific way. Females with short telomeres had a delayed age at first breeding and a lower fecundity rate than females with long telomeres, whereas those differences were not recorded in males. Our findings support most predictions adapted from the anti-cancer hypothesis, but none of those made under the resource allocation trade-off hypothesis. Results are in line with an increasing body of evidence suggesting that resource allocation trade-offs alone cannot explaining the diversity of telomere length in adult somatic cells and life-histories observed across the tree of life.

scholarly journals I.—A Contribution to the Life-Histories of the Cod and Whiting

1905 ◽  
Vol 40 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Arthur T. Masterman
Keyword(s):  
Life History ◽  
Life Histories ◽  
Great Majority ◽  
Early Spring ◽  
Spawning Period ◽  
The Third ◽  
Pelagic Eggs ◽  
Main Period

Considering the abundance of this gadoid, it is a matter for surprise that our knowledge of its life-history is not more complete. The work of Prof. Sars upon the cod in Norwegian waters is well known, and need not be referred to in any detail here. It is, however, important to avoid the assumption that his account will apply in every detail to the cod of British waters.In 1883 Prof. M'Intosh showed that the cod spawned in early spring and that spawning was effected outside the territorial limit. Dr Fulton, from an examination of a number of captured specimens, was led to the same conclusion; and further, that the cod, whilst having an extended spawning period reaching from January to June, must be regarded as having a main period of February, March, and April, the great majority of individuals spawning in the month of March. Thus whilst 40 per cent, of the fish examined in March were mature, the proportion fell to 16 per cent, for February and April, and 10 per cent, for May. In estimating the growth of this species, by the method pursued below, it is probably most correct to regard the true spawning period as including the months of February, March, April, and May. A study of the distribution of pelagic eggs off the Frith of Forth leads to a similar conclusion. From this latter source the spawning period of the cod can be defined as extending from the third week in February to the second week in May, with a maximum in early April.

scholarly journals Effect of self-fertilization on Biomphalaria tenagophila (Orbigny, 1835) (Pulmonata: Planorbidae)

1998 ◽  
Vol 21 (4) ◽  
pp. 477-478 ◽  
Author(s):  
Roseli Tuan ◽  
Luiz Carlos Gomes Simões
Keyword(s):  
Sexual Maturity ◽  
Freshwater Snail ◽  
Simultaneous Hermaphrodite ◽  
Reproductive Parameters ◽  
Shell Size ◽  
Self Fertilization ◽  
The Cross ◽  
Cross Fertilization

Biomphalaria tenagophila is a simultaneous hermaphrodite freshwater snail, which can breed by self and cross-fertilization. It is, therefore, well suited for studying reproduction as an evolutive strategy. Several characteristics (shell size and age at sexual maturity, egg fecundity and fertility) were analyzed in four consecutive self-fertilized generations and compared to cross-fertilized individuals. The reproductive parameters were similar in the two groups. Shell size was significantly greater in the fourth self-fertilized generation than in the cross-fertilized individuals.

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