Abstract:The persistence of an invasive species is influenced by its reproductive ecology, and a successful control program must operate on this premise. However, the reproductive ecology of invasive species may be enigmatic due to factors that also limit their management, such as cryptic coloration and behavior. We explored the mating and reproductive ecology of the invasive Brown Treesnake (BTS: Boiga irregularis) by reconstructing a multigenerational genomic pedigree based on 654 single nucleotide polymorphisms for … Show more
“…The presence of whole genomic DNA was confirmed by separating 5 μL of each DNA sample on a 1.5% agarose gel for 60 minutes at 100 mV and visualizing with SYBR TM Safe DNA gel stain (Invitrogen TM ). DNA was then prepared for high throughput, parallel sequencing using a double-digest restriction-site associated DNA (ddRAD) library preparation protocol [ 40 ], slightly modified from that described for snakes by Levine et al [ 41 ]. Approximately 1000 ng DNA of each sample was digested in a thermocycler for 16 hours at 37°C with 1 μL each of FastDigest TM restriction enzymes PstI and MspI (Thermo Scientific TM ), 5 μL FastDigest 10× buffer (Thermo Scientific TM ) and 3 μL molecular grade water.…”
Females of many vertebrate species have the capacity to store sperm within their reproductive tracts for prolonged periods of time. Termed long-term sperm storage, this phenomenon has many important physiological, ecological, and evolutionary implications, particularly to the study of mating systems, including male reproductive success and post-copulatory sexual selection. Reptiles appear particularly predisposed to long-term sperm storage, with records in most major lineages, with a strong emphasis on turtles and squamates (lizards, snakes, but not the amphisbaenians). Because facultative parthenogenesis is a competing hypothesis to explain the production of offspring after prolonged separation from males, the identification of paternal alleles through genetic analysis is essential. However, few studies in snakes have undertaken this. Here, we report on a wild-collected female Western Diamond-backed Rattlesnake, Crotalus atrox, maintained in isolation from the time of capture in September 1999, that produced two healthy litters approximately one and six years post capture. Genetic analysis of the 2005 litter, identified paternal contribution in all offspring, thus rejecting facultative parthenogenesis. We conclude that the duration of long-term sperm storage was approximately 6 years (71 months), making this the longest period over which a female vertebrate has been shown to store sperm that resulted in the production of healthy offspring.
“…The presence of whole genomic DNA was confirmed by separating 5 μL of each DNA sample on a 1.5% agarose gel for 60 minutes at 100 mV and visualizing with SYBR TM Safe DNA gel stain (Invitrogen TM ). DNA was then prepared for high throughput, parallel sequencing using a double-digest restriction-site associated DNA (ddRAD) library preparation protocol [ 40 ], slightly modified from that described for snakes by Levine et al [ 41 ]. Approximately 1000 ng DNA of each sample was digested in a thermocycler for 16 hours at 37°C with 1 μL each of FastDigest TM restriction enzymes PstI and MspI (Thermo Scientific TM ), 5 μL FastDigest 10× buffer (Thermo Scientific TM ) and 3 μL molecular grade water.…”
Females of many vertebrate species have the capacity to store sperm within their reproductive tracts for prolonged periods of time. Termed long-term sperm storage, this phenomenon has many important physiological, ecological, and evolutionary implications, particularly to the study of mating systems, including male reproductive success and post-copulatory sexual selection. Reptiles appear particularly predisposed to long-term sperm storage, with records in most major lineages, with a strong emphasis on turtles and squamates (lizards, snakes, but not the amphisbaenians). Because facultative parthenogenesis is a competing hypothesis to explain the production of offspring after prolonged separation from males, the identification of paternal alleles through genetic analysis is essential. However, few studies in snakes have undertaken this. Here, we report on a wild-collected female Western Diamond-backed Rattlesnake, Crotalus atrox, maintained in isolation from the time of capture in September 1999, that produced two healthy litters approximately one and six years post capture. Genetic analysis of the 2005 litter, identified paternal contribution in all offspring, thus rejecting facultative parthenogenesis. We conclude that the duration of long-term sperm storage was approximately 6 years (71 months), making this the longest period over which a female vertebrate has been shown to store sperm that resulted in the production of healthy offspring.
“…Here, mating success is defined as the number of mates with which an individual produced offspring, and reproductive success as the number of offspring produced by an individual, following Levine et al . [ 28 ]. Figure 1.…”
Section: Methodsmentioning
confidence: 99%
“…Using these parentage assignments, the total mating and reproductive success for males and females over the course of the study were quantified (figures 1 and 2; electronic supplementary material), as were annual mating and reproductive success for males and females (electronic supplementary material). Here, mating success is defined as the number of mates with which an individual produced offspring, and reproductive success as the number of offspring produced by an individual, following Levine et al [28].…”
Decades of research on sexual selection have demonstrated that ‘conventional’ Darwinian sex roles are common in species with anisogamous gametes, with those species often exhibiting male-biased sexual selection. Yet, mating system characteristics such as long-term sperm storage and polyandry have the capacity to disrupt this pattern. Here, these ideas were explored by quantifying sexual selection metrics for the western diamond-backed rattlesnake (
Crotalus atrox
). A significant standardized sexual selection gradient was not found for males (
β
SS
= 0.588,
p
= 0.199) or females (
β
SS
= 0.151,
p
= 0.664), and opportunities for sexual selection (
I
s
) and selection (
I
) did not differ between males (
I
s
= 0.069,
I
= 0.360) and females (
I
s
= 0.284,
I
= 0.424; both
p
> 0.05). Furthermore, the sexes did not differ in the maximum intensity of precopulatory sexual selection (males:
s′
max
= 0.155, females:
s′
max
= 0.080;
p
> 0.05). Finally, there was no evidence that male snout–vent length, a trait associated with mating advantage, is a target of sexual selection (
p
> 0.05). These results suggest a lack of male-biased sexual selection in this population. Mating system characteristics that could erode male-biased sexual selection, despite the presence of conventional Darwinian sex roles, are discussed.
“…However, this information is lacking for most amphibian species in the wild (O'Brien et al 2018). Pedigree information from direct records or parentage re-construction from genetic methods can provide robust inferences about the number of successfully breeding males and females and the rates of polygamy of each sex, therefore allowing exploration of the mating system and breeding success of target species (Vieites et al 2004;Rovelli et al 2015;Levine et al 2019). The sibship frequency method infers the parentage of an offspring sample jointly with an estimate of the effective population size (Wang 2009b;Mangold et al 2015).…”
Section: Introductionmentioning
confidence: 99%
“…2015; Levine et al . 2019). The sibship frequency method infers the parentage of an offspring sample jointly with an estimate of the effective population size (Wang 2009b; Mangold et al .…”
In the face of worldwide amphibian declines, integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust, reliable, and comparable assessments of demographic dynamics. The Iberian painted frog (Discoglossus galganoi) is endemic to Spain and Portugal and shows decreasing population trends across its range, but few studies have attempted to estimate census sizes or assess genetic diversity in wild populations, and little is known about their reproductive biology. We applied an integrative approach based on the combination of capture-mark-recapture data and multilocus genotypes to monitor a breeding population of D. galganoi in central Spain during two consecutive breeding seasons, focusing on the estimation of demographic parameters and their temporal variation. Specifically, we estimated the number of adults (N a), the effective population size (N e), and the effective number of breeders (N b), as well as survival and migration rates. We documented a >50% decrease in the estimated number of adults of both sexes between the breeding seasons of 2018 and 2019, probably associated with reduced rainfall in the latter. Estimates of N b and the N b /N a ratio were low in both seasons, with a 20-30% decrease in N b and a 47% increase in the N b /N a ratio in 2019. Based on the reconstruction of pedigrees from larval and adult genotypes, we provide the first genetic evidence of polygamy in males and females of D. galganoi and the first estimates of breeding success in the species.
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