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Article Reference Impact of Laying Date and Fire Ants on Hatchlings of Chelonoidis porteri on Santa Cruz Island, Galápagos, Ecuador
Chelonoidis land tortoises are iconic species endemic to the Galápagos Islands of Ecuador. Their populations have been dramatically reduced by human activities in the last three centuries, including indirect effects such as the introduction of invasive species. We investigated the mortality of eggs and hatchlings in 48 nests of Chelonoidis porteri on Santa Cruz Island with regard to various mortality causes such as the occurrence of fire ants and the date of laying. The average mortality rate was 0.56. Tropical Fire Ants (Solenopsis geminata) were present within 1 m of 75% of the C. porteri nests, and we encountered fire ants in 12.5% of excavated nests. We found no relationship between Tropical Fire Ant abundance and C. porteri egg and hatchling survivorship. We observed no signs of mold inside the nests. We determined that early deposition dates were associated with lower clutch survival and identified egg development as the critical life stage. Finally, we discuss the potential impacts of fire ants and climate change on tortoise survival and reproduction and stress the importance of taking these factors into account for the conservation of the endemic land tortoises of the Galápagos
Located in Library / RBINS Staff Publications 2018
Article Reference Introduction history and genetic diversity of the invasive ant Solenopsis geminata in the Gala´pagos Islands
The Gala´pagos Islands constitute one of the most pristine tropical systems on Earth. However, the complex and fragile equilibrium of native species is threatened by invasive species, among which is one of the most successful ants in the world, the tropical fire ant, Solenopsis geminata. We characterized the genetic structure and diversity of populations of S. geminata in the Galapagos Islands and unravelled the archipelago colonization by combining Bayesian clustering methods and coalescent-based scenario testing. Using 12 microsatellite markers and one mitochondrial DNA fragment (COI), we analysed individuals collected in all main invaded islands of the archipelago and from the native areas in Costa Rica and mainland Ecuador. We also used mitochondrial DNA to infer evolutionary relationships of samples collected in Galapagos Islands, Ecuador, Costa Rica and other Latin American countries. Our results showed that genetic diversity was significantly lower in Galapagos Islands and mainland Ecuador populations when compared to Costa Rican populations, and that samples from Galapagos Islands and mainland Ecuador (Guayaquil) clustered in a single group and all share a single mtDNA haplotype. Approximate Bayesian Computation favoured a scenario assuming that populations from Galapagos Islands diverged from mainland Ecuador. The city of Guyaquil, an obligatory hub for tourism and trade, could act as a bridgehead.
Located in Library / RBINS Staff Publications 2018
Article Reference First record of the invasive longhorn crazy ant, Paratrechina longicornis (Latreille, 1802) (Hymenoptera: Formicidae) from Mt. Elgon, eastern Uganda
We report the first observation of the invasive longhorn crazy ant (Paratrechina longicornis) in the Mount Elgon region of eastern Uganda. About 43 000 ants were sampled in 256 locations throughout the Ugandan foot slopes of Mt. Elgon in the years 2014, 2015 and 2016. We found P. longicornis in five locations in and around the town of Budadiri, Sironko district. The visual species identification was confirmed by COI gene-based DNA barcoding. That this species was found in only a small area suggests that it has only been recently introduced. The impact that P. longicornis will have on the local agricultural system or the biodiversity within the Mount Elgon National Park remains unclear. The Mt. Elgon region is a unique key biodiversity area where baseline data can be collected now to quantify the effects of P. longicornis as it increases its distribution within the region
Located in Library / RBINS Staff Publications 2019
Article Reference Understanding taxonomic and nomenclatural instability – a case study of the Manila clam
Located in Library / RBINS Staff Publications 2019
Article Reference Highly polymorphic mitochondrial DNA and deceiving haplotypic differentiation: implications for assessing population genetic differentiation and connectivity
Background Hyperdiverse mtDNA with more than 5% of variable synonymous nucleotide sites can lead to erroneous interpretations of population genetic differentiation patterns and parameters (φST, DEST). We illustrate this by using hyperdiverse mtDNA markers to infer population genetic differentiation and connectivity in Melarhaphe neritoides, a NE Atlantic (NEA) gastropod with a high dispersal potential. We also provide a recent literature example of how mtDNA hyperdiversity may have misguided the interpretation of genetic connectivity in the crab Opecarcinus hypostegus. Results mtDNA variation surveyed throughout the NEA showed that nearly all M. neritoides specimens had haplotypes private to populations, suggesting at first glance a lack of gene flow and thus a strong population genetic differentiation. Yet, the bush-like haplotype network, though visually misleading, showed no signs of phylogeographic or other haplotype structuring. Coalescent-based gene flow estimates were high throughout the NEA, irrespective of whether or not mtDNA hyperdiversity was reduced by removing hypervariable sites. Conclusions Melarhaphe neritoides seems to be panmictic over the entire NEA, which is consistent with its long-lived pelagic larval stage. With hyperdiverse mtDNA, the apparent lack of shared haplotypes among populations does not necessarily reflect a lack of gene flow and/or population genetic differentiation by fixation of alternative haplotypes (DEST ≈ 1 does not a fortiori imply φST ≈ 1), but may be due to (1) a too low sampling effort to detect shared haplotypes and/or (2) a very high mutation rate that may conceal the signal of gene flow. Hyperdiverse mtDNA can be used to assess connectivity by coalescent-based methods. Yet, the combined use of φST and DEST can provide a reasonable inference of connectivity patterns from hyperdiverse mtDNA, too.
Located in Library / RBINS Staff Publications 2019
Article Reference New discoveries of tetrapods (ichthyostegid-like and whatcheeriid-like) in the Famennian (Late Devonian) localities of Strud and Becco (Belgium).
Located in Library / RBINS Staff Publications 2016
Article Reference Micropalaeontological dating of the Prémontré mammal fauna (MP10, Prémontré Sands, EECO, early late Ypresian, Paris Basin).
At their type locality the Prémontré Sands contain fairly well-diversified organic-walled microfossil assemblages attributable to the lower part of dinoflagellate cyst Zone D9 and indicating a transition from an estuarine to a lagoonal depositional regime, up-section as well as laterally. Identical assemblages have been recorded in the inner to mid-neritic Merelbeke Clay Member in Belgium, allowing the Prémontré Sands to be positioned within lower NP13 and early Chron C22r. The deposition of the MP10 Prémontré mammal fauna is estimated to postdate the onset of both NP13 and Chron C22r, which are nearly coincident, by about 200 to 300 kyr. The biostratigraphic dating refers this deposit to the early late Ypresian and to the final phase of the Early Eocene Climatic Optimum (EECO) at about 50.4 to 50.3 million years ago. The Prémontré Sands, as well as their distal equivalent the Merelbeke Clay Member, were deposited following a major sea-level rise, the highest of the late Ypresian in the southern North Sea Basin s.l. (including the Paris Basin). They are separated from the overlying “Glauconie grossière” (zone NP14; middle part of zone D9) by a hiatus of approximately 2.5 myr.
Located in Library / RBINS Staff Publications 2016
Article Reference Fitness-heterozygosity associations differ between male and female winter moths Operophtera brumata L.
The association between heterozygosity and fitness is positive but weak on average and varies between studies. inbreeding has been invoked as the driving force between the positive heterozygosity-fitness associations, yet in spatio-temporally stable environments a negative correlation is expected. Furthermore, different patterns can arise because of the effects of natural selection on different loci and variation can be expected among groups of individuals that experience different levels of stress. In this paper we report on fitness-heterozygosity associations in the winter moth for six allozyme loci. The relationship is estimated for males and females separately, in four areas differing in their degree of fragmentation, and variation among loci is modelled. We introduce a linear mixed model framework to achieve this analysis. This approach differs from more traditional (multiple) regression analyses and allows testing specific interactions. We show that fitness, as estimated by body size, is negatively correlated with heterozygosity, but only so in females. This association does not vary significantly among loci and the four areas. We speculate that a trade-off between fitness-consequences of inbreeding and outbreeding at different stages of the winter moth life cycle could explain the observed patterns.
Located in Associated publications / Belgian Journal of Zoology / Bibliographic References
Article Reference A comparison of gene flow estimates based on private allele frequencies.
The frequency of private alleles is often used to assess the amount of gene flow (Nm) between populations, with the equations proposed by SLATKIN (1985b) and by SLATKIN and BARTON (1989). Although these equations express the same relationship, they may yield different estimates of gene flow for the same data. These differences increase with decreasing frequencies of private alleles. Comparisons of Nm estimates, based on different equations can therefore be misleading. It is advisable to use these equations method only to distinguish between Nm > 1 and Nm < 1.
Located in Associated publications / Belgian Journal of Zoology / Bibliographic References
Article Reference First record of the lanternfly genus Limois Stål, 1863 in Vietnam with a new species, L. sonlaensis sp. nov. (Hemiptera: Fulgoromorpha: Fulgoridae)
Located in Library / RBINS Staff Publications 2022 OA