ORCID Profile
0000-0003-1266-9134
Current Organisations
Okinawa Institute of Science and Technology Graduate University
,
Université Libre de Bruxelles
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Publisher: Wiley
Date: 29-04-2022
DOI: 10.1111/SYEN.12548
Abstract: Termites are social cockroaches distributed throughout warm temperate and tropical ecosystems. The ancestor of modern termites roamed the earth during the early Cretaceous, suggesting that both vicariance and overseas dispersal may have shaped the distribution of early erging termites. We investigate the historical biogeography of three early erging termite families –Stolotermitidae, Hodotermitidae and Archotermopsidae (clade Teletisoptera) – using the nuclear rRNA genes and mitochondrial genomes of 27 s les. Our analyses confirm the monophyly of Teletisoptera, with Stolotermitidae erging from Hodotermitidae + Archotermopsidae approximately 100 Ma. Although Hodotermitidae are monophyletic, our results demonstrate the paraphyly of Archotermopsidae. Phylogenetic analyses indicate that the timing of ergence among the main lineages of Hodotermitidae + Archotermopsidae are compatible with vicariance. In the Stolotermitidae, however, the common ancestors of modern Porotermes Hagen and Stolotermes Hagen are roughly as old as 20 and 35 Ma, respectively, indicating that the presence of these genera in South America, Africa and Australia involved over‐water dispersals. Overall, our results suggest that early erging termite lineages acquired their current distribution through a combination of over‐water dispersals and dispersal via land bridges. We clarify the classification by resolving the paraphyly of Archotermopsidae, restricting the family to Archotermopsis Desneux and Zootermopsis Emerson and elevating Hodotermopsinae ( Hodotermopsis Holmgren) as Hodotermopsidae ( status novum ).
Publisher: Wiley
Date: 17-08-2023
DOI: 10.1111/SYEN.12607
Abstract: While new species of termites are described every year, the description of species distant from every known termite species is rare. In this paper, we describe one such species, Engelitermes zambo sp.n. , an African Termitidae belonging to an entirely new lineage of termites for which we create a new subfamily, Engelitermitinae subfam.n. The subfamily status of Engelitermitinae was supported by termite phylogenetic trees, including sequences from the four existing s les of E. zambo sp.n. , which, albeit with low bootstrap supports, placed Engelitermes gen.n. on a long branch sister to Forficulitermes , the two of which formed the sister group of a clade comprising Cubitermitinae, Nasutitermitinae, Syntermitinae and all other Termitinae. The sister relationship between Engelitermes gen.n. and Forficulitermes is further supported by the similar gut structure of their workers. In contrast, the soldiers of Engelitermes gen.n. resemble those of Cephalotermes . Our phylogenetic analyses, including all clades of Termitinae, call for a global taxonomic revision of the Termitinae subfamily names. Finally, our study highlights that new unique termite lineages are still awaiting to be described.
Publisher: Proceedings of the National Academy of Sciences
Date: 13-12-2021
Abstract: The evolution of asexuality is thought to be prevented when males play a critical role beyond that of gamete provision. We demonstrated high numbers of neo-sex chromosomes and enhanced heterozygosity in males of the termite Glyptotermes nakajimai , which appears to compensate for inbreeding within termite colonies. Furthermore, we showed that two asexual G . nakajimai lineages have evolved via independent intraspecific hybridizations between sexual lineages with differing diploid chromosome numbers. This has resulted in markedly higher levels of heterozygosity of females than males in the sexual lineage. Our study illustrates that asexual females may replace the role of males in maintaining heterozygosity, implying a route to the evolution of asexuality.
Publisher: Oxford University Press (OUP)
Date: 05-2022
Abstract: Termites are major decomposers in terrestrial ecosystems and the second most erse lineage of social insects. The Kalotermitidae form the second-largest termite family and are distributed across tropical and subtropical ecosystems, where they typically live in small colonies confined to single wood items inhabited by in iduals with no foraging abilities. How the Kalotermitidae have acquired their global distribution patterns remains unresolved. Similarly, it is unclear whether foraging is ancestral to Kalotermitidae or was secondarily acquired in a few species. These questions can be addressed in a phylogenetic framework. We inferred time-calibrated phylogenetic trees of Kalotermitidae using mitochondrial genomes of ∼120 species, about 27% of kalotermitid ersity, including representatives of 21 of the 23 kalotermitid genera. Our mitochondrial genome phylogenetic trees were corroborated by phylogenies inferred from nuclear ultraconserved elements derived from a subset of 28 species. We found that extant kalotermitids shared a common ancestor 84 Ma (75–93 Ma 95% highest posterior density), indicating that a few disjunctions among early- erging kalotermitid lineages may predate Gondwana breakup. However, most of the ∼40 disjunctions among biogeographic realms were dated at & Ma, indicating that transoceanic dispersals, and more recently human-mediated dispersals, have been the major drivers of the global distribution of Kalotermitidae. Our phylogeny also revealed that the capacity to forage is often found in early- erging kalotermitid lineages, implying the ancestors of Kalotermitidae were able to forage among multiple wood pieces. Our phylogenetic estimates provide a platform for critical taxonomic revision and future comparative analyses of Kalotermitidae.
Publisher: Cold Spring Harbor Laboratory
Date: 03-12-2021
DOI: 10.1101/2021.12.01.470872
Abstract: Madagascar is home to many endemic plant and animal species owing to its ancient isolation from other landmasses. This unique fauna includes several lineages of termites, a group of insects known for their key role in organic matter decomposition in many terrestrial ecosystems. How and when termites colonised Madagascar remains unknown. In this study, we used 601 mitochondrial genomes, 93 of which were generated from Madagascan s les, to infer the global historical biogeography of Neoisoptera, a lineage containing upwards of 80% of described termite species. Our results indicate that Neoisoptera colonised Madagascar between seven to ten times independently during the Miocene, between 8.4-16.6 Ma (95% HPD: 6.1-19.9 Ma). This timing matches that of the colonization of Australia by Neoisoptera. Furthermore, the taxonomic composition of the Neoisopteran fauna of Madagascar and Australia are strikingly similar, with Madagascar harbouring an additional two lineages absent from Australia. Therefore, akin to Australia, Neoisoptera colonised Madagascar during the global expansion of grasslands, possibly helped by the ecological opportunities arising from the spread of this new biome.
Publisher: Cold Spring Harbor Laboratory
Date: 03-12-2021
DOI: 10.1101/2021.12.02.471008
Abstract: Termites are social cockroaches distributed throughout warm temperate and tropical ecosystems. The ancestor of modern termites (crown-Isoptera) occurred during the earliest Cretaceous, approximately 140 million years ago, suggesting that both vicariance through continental drift and overseas dispersal may have shaped the distribution of early erging termite lineages. We reconstruct the historical biogeography of three early erging termite families – Stolotermitidae, Hodotermitidae, and Archotermopsidae – using the nuclear rRNA genes and mitochondrial genomes of 27 s les. Our analyses confirmed the monophyly of Stolotermitidae + Hodotermitidae + Archotermopsidae (clade Teletisoptera), with Stolotermitidae erging from a monophyletic Hodotermitidae + Archotermopsidae approximately 100.3 Ma (94.3–110.4 Ma, 95% HPD), and with Archotermopsidae paraphyletic to a monophyletic Hodotermitidae. The Oriental Archotermopsis and the Nearctic Zootermopsis erged 50.8 Ma (40.7–61.4 Ma, 95% HPD) before land connections between the Palearctic region and North America ceased to exist. The African Hodotermes + Microhodotermes erged from Anacanthotermes , a genus found in Africa and Asia, 32.1 Ma (24.8–39.9 Ma, 95% HPD), and the most recent common ancestor of Anacanthotermes lived 10.7 Ma (7.3–14.3 Ma, 95% HPD), suggesting that Anacanthotermes dispersed to Asia using the land bridge connecting Africa and Eurasia ∼18–20 Ma. In contrast, the common ancestors of modern Porotermes and Stolotermes lived 20.2 Ma (15.7–25.1 Ma, 95% HPD) and 26.6 Ma (18.3–35.6 Ma, 95% HPD), respectively, indicating that the presence of these genera in South America, Africa, and Australia involved over-water dispersals. Our results suggest that early erging termite lineages acquired their current distribution through a combination of over-water dispersals and dispersal via land bridges. We clarify the classification by resolving the paraphyly of Archotermopsidae, restricting the family to Archotermopsis and Zootermopsis , and elevating Hodotermopsinae ( Hodotermopsis ) as Hodotermopsidae ( status novum ).
Publisher: Cold Spring Harbor Laboratory
Date: 10-12-2021
DOI: 10.1101/2021.12.09.472027
Abstract: The phylogenetic history of termites has been investigated using mitochondrial genomes and transcriptomes. However, both sets of markers have specific limitations. Mitochondrial genomes represent a single genetic marker likely to yield phylogenetic trees presenting incongruences with species trees, and transcriptomes can only be obtained from well-preserved s les. In contrast, ultraconserved elements (UCEs) include a great many independent markers that can be retrieved from poorly preserved s les. Here, we designed termite-specific baits targeting 50,616 UCE loci. We tested our UCE bait set on 42 s les of termites and three s les of Cryptocercus , for which we generated low-coverage highly-fragmented genome assemblies and successfully extracted in silico between 3,426 to 42,860 non-duplicated UCEs per s le. Our maximum likelihood phylogenetic tree, reconstructed using the 5,934 UCE loci retrieved from upward of 75% of s les, was congruent with transcriptome-based phylogenies, demonstrating that our UCE bait set is reliable and phylogenetically informative. Combined with non-destructive DNA extraction protocols, our UCE bait set provides the tool needed to carry out a global taxonomic revision of termites based on poorly preserved specimens such as old museum s les. The Termite UCE database is maintained at: ist/TER-UCE-DB/ .
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/IS16089
Abstract: Since the inception of Linnaean taxonomy, termite species and genus descriptions have been mostly based on the morphology of soldiers, sometimes complemented by alate characters, though these are seldom discriminant. However, narrowly soldier-based descriptions may overemphasise ancestral characters and lead to the establishment of non-monophyletic taxa. In this paper, we used an integrative taxonomic approach that incorporates the morphology of all castes, including workers, as well as molecular and chemical data, to describe Palmitermes impostor Hellemans & Roisin, 2017 (Termitidae:Termitinae), a new termite genus and species from French Guiana. Although the soldiers of P. impostor resemble those of Termes Linnaeus, 1758, the digestive tract and mandibles of workers suggest that Palmitermes is closely related to Cavitermes Emerson, 1925. The sister-group relationship between Palmitermes and Cavitermes was confirmed by a phylogenetic reconstruction based on full mitochondrial genome sequences as well as by the comparison of the profiles of cuticular hydrocarbons of workers with those of related taxa. Our study illustrates the benefits of using an integrative taxonomic approach to describe new taxa and the pitfalls of using soldier morphology as the exclusive set of characters in termite systematics.
Publisher: Cold Spring Harbor Laboratory
Date: 20-01-2023
DOI: 10.1101/2023.01.17.524483
Abstract: Rates of nucleotide substitution vary substantially across the Tree of Life, with potentially confounding effects on phylogenetic and evolutionary analyses. A large acceleration in mitochondrial substitution rate occurs in the cockroach family Nocticolidae, which predominantly inhabit subterranean environments. To evaluate the impacts of this among-lineage rate heterogeneity on estimates of phylogenetic relationships and evolutionary timescales, we analysed nuclear ultraconserved elements (UCEs) and mitochondrial genomes from nocticolids and other cockroaches. Substitution rates were substantially elevated in nocticolid lineages compared with other cockroaches, especially in mitochondrial protein-coding genes. This disparity in evolutionary rates is likely to have led to different evolutionary relationships being supported by phylogenetic analyses of mitochondrial genomes and UCE loci. Furthermore, Bayesian dating analyses using relaxed-clock models inferred much deeper ergence times compared with a flexible local clock. Our phylogenetic analysis of UCEs, which is the first genome-scale study to include all ten major cockroach families, unites Corydiidae and Nocticolidae and places Anaplectidae as the sister lineage to the rest of Blattoidea. We uncover an extraordinary level of genetic ergence in Nocticolidae, including two highly distinct clades that separated ∼115 million years ago despite both containing representatives of the genus Nocticola . The results of our study highlight the potential impacts of high among-lineage rate variation on estimates of phylogenetic relationships and evolutionary timescales.
Publisher: Wiley
Date: 21-04-2023
DOI: 10.1111/ECOG.06463
Abstract: Madagascar is home to many endemic plant and animal species owing to its ancient isolation from other landmasses. This unique fauna includes several lineages of termites, a group of insects known for their key role in organic matter decomposition in many terrestrial ecosystems. How and when termites colonised Madagascar remains unknown. In this study, we used 601 mitochondrial genomes, 93 of which were generated from Malagasy s les, to infer the global historical biogeography of Neoisoptera, a lineage containing more than 80% of described termite species. Our results indicate that Neoisoptera colonised Madagascar between 7 and 10 times independently during the Miocene, between 8.4 and 16.6 Ma (95% HPD: 6.1–19.9 Ma). This timing matches that of the colonization of Australia by Neoisoptera. Furthermore, the taxonomic composition of the Neoisopteran fauna of Madagascar and Australia are strikingly similar, with Madagascar harbouring an additional two lineages absent from Australia. Therefore, akin to Australia, Neoisoptera colonised Madagascar during the global expansion of grasslands, possibly helped by the ecological opportunities arising from the spread of this new biome.
Publisher: The Royal Society
Date: 25-05-2022
Abstract: Termites feed on vegetal matter at various stages of decomposition. Lineages of wood- and soil-feeding termites are distributed across terrestrial ecosystems located between 45°N and 45°S of latitude, a distribution they acquired through many transoceanic dispersal events. While wood-feeding termites often live in the wood on which they feed and are efficient at dispersing across oceans by rafting, soil-feeders are believed to be poor dispersers. Therefore, their distribution across multiple continents requires an explanation. Here, we reconstructed the historical biogeography and the ancestral diet of termites using mitochondrial genomes and δ 13 C and δ 15 N stable isotope measurements obtained from 324 termite s les collected in five biogeographic realms. Our biogeographic models showed that wood-feeders are better at dispersing across oceans than soil-feeders, further corroborated by the presence of wood-feeders on remote islands devoid of soil-feeders. However, our ancestral range reconstructions identified 33 dispersal events among biogeographic realms, 18 of which were performed by soil-feeders. Therefore, despite their lower dispersal ability, soil-feeders performed several transoceanic dispersals that shaped the distribution of modern termites.
Publisher: Cold Spring Harbor Laboratory
Date: 24-05-2023
DOI: 10.1101/2023.05.22.541647
Abstract: Fossils encompassing multiple in iduals provide rare direct evidence of behavioral interactions among extinct organisms. However, the fossilization process can alter the spatial relationship between in iduals and hinder behavioral reconstruction. Here, we report a Baltic amber inclusion preserving a female-male pair of the extinct termite species Electrotermes affinis . The head-to-abdomen contact in the fossilized pair resembles the tandem courtship behavior of extant termites, although their parallel body alignment differs from the linear alignment typical of tandem runs. To solve this inconsistency, we simulated the first stage of amber formation, the immobilization of captured organisms, by exposing living termite tandems to sticky surfaces. We found that the posture of the fossilized pair matches trapped tandems and differs from untrapped tandems. Thus, the fossilized pair likely is a tandem running pair, representing the first direct evidence of the mating behavior of extinct termites. Furthermore, by comparing the positions of partners on a sticky surface and in the amber inclusion, we estimated to 67% the probability that the leader role in the fossilized tandem was performed by a male. Our results demonstrate that past behavioral interactions can be reconstructed despite the spatial distortion of body poses during fossilization. Our taphonomic approach clarifies how certain behaviors can be inferred from fossil occurrences.
Publisher: The Royal Society
Date: 21-06-2023
Abstract: Termites host erse communities of gut microbes, including many bacterial lineages only found in this habitat. The bacteria endemic to termite guts are transmitted via two routes: a vertical route from parent colonies to daughter colonies and a horizontal route between colonies sometimes belonging to different termite species. The relative importance of both transmission routes in shaping the gut microbiota of termites remains unknown. Using bacterial marker genes derived from the gut metagenomes of 197 termites and one Cryptocercus cockroach, we show that bacteria endemic to termite guts are mostly transferred vertically. We identified 18 lineages of gut bacteria showing cophylogenetic patterns with termites over tens of millions of years. Horizontal transfer rates estimated for 16 bacterial lineages were within the range of those estimated for 15 mitochondrial genes, suggesting that horizontal transfers are uncommon and vertical transfers are the dominant transmission route in these lineages. Some of these associations probably date back more than 150 million years and are an order of magnitude older than the cophylogenetic patterns between mammalian hosts and their gut bacteria. Our results suggest that termites have cospeciated with their gut bacteria since first appearing in the geological record.
Location: Japan
Location: No location found
Location: No location found
No related grants have been discovered for Simon Hellemans.