Menno Schilthuizen - Academia.edu (original) (raw)

Papers by Menno Schilthuizen

Journal of Avian Biology, Feb 1, 2005

phylogenetic analysis of the white-crowned forktail Enicurus leschenaulti in Borneo. Á/ J. Avian ... more phylogenetic analysis of the white-crowned forktail Enicurus leschenaulti in Borneo. Á/ J. Avian Biol. 36: 96 Á/101. Comparison of 1017 nucleotides of mitochondrial ND2 and ND3 DNA sequences of 26 individuals of white-crowned forktail Enicurus leschenaulti from SE Asia revealed multiple evolutionary lineages within Borneo. Montane birds were genetically homogeneous across localities, but diverged by more than 4.3% from all other samples. Lowland birds formed two distinct clades, one consisting of individuals from northern Borneo, and the other including individuals from western Borneo, as well as Sumatra and Malaya. Relationships among the subspecies were not well resolved. These findings indicate another example of montane and north Bornean endemicity, support the separation of the montane and lowland species, and define areas of conservation interest.

Entomologische Berichten, 1988

The rare Central-european species Dirhagus lepidus Rosenhauer was found for the first time in The... more The rare Central-european species Dirhagus lepidus Rosenhauer was found for the first time in The Nether¬ lands: one 9 in an old beechstub. Nearest known locations are in the northeast of France. Some differences between D. lepidus and D. pygmaeus (Fabricius) are discussed.

Journal of Tropical Biology & Conservation (JTBC)

Metallyticus is a genus of rare mantids, occurring mostly in SouthEast Asia. Five species have be... more Metallyticus is a genus of rare mantids, occurring mostly in SouthEast Asia. Five species have been described. However, their ecology and behaviour remain virtually unknown. In this study, we describe a small population of Metallyticus splendidus Westwood, 1889 on a dead dipterocarp tree standing in disturbed tropical rainforest around Danau Girang Field Centre, Sabah, Malaysia. At dawn, in the afternoon and at night, four individuals, two adults and two nymphs, were monitored. Our findings confirm earlier behavioural observations: they hold their bodies flat when running. We did not observe any lurking behaviour: the mantids were walking fast across the tree stem and in tree holes. M. splendidus was found at dawn, in the afternoon, and at night only on this single dead tree in a plot of 50 X 50 m. This suggests that M. splendidus is day and night-active and that its habitat is restricted to dead standing trees. We failed to find other individuals on other dead as well as living tre...

Contributions to zoology, Dec 22, 2017

In animals, cell polarity may initiate symmetry breaking very early in development, ultimately le... more In animals, cell polarity may initiate symmetry breaking very early in development, ultimately leading to whole-body asymmetry. Helical sperm cells, which occur in a variety of animal clades, are one class of cells that show clearly visible bilateral asymmetry. We used scanning-electron microscopy to study coiling direction in helical sperm cells in two groups of animals that have figured prominently in the sperm morphology literature, namely land snails, Stylommatophora (514 spermatozoa, from 27 individuals, belonging to 8 species and 4 families) and songbirds, Passeriformes (486 spermatozoa, from 26 individuals, belonging to 18 species and 8 families). We found that the snail sperm cells were consistently dextral (clockwise), whereas the bird sperm cells were consistently sinistral (counterclockwise). We discuss reasons why this apparent evolutionary conservatism of sperm cell chirality may or may not be related to whole-body asymmetry.

Journal of Tropical Biology & Conservation (JTBC), Oct 15, 2016

In Borneo, the forest type that supports the largest number of species, the tropical lowland rain... more In Borneo, the forest type that supports the largest number of species, the tropical lowland rainforest, is decreasing rapidly. To estimate what is the general effect of this habitat degradation and loss on birds, this study looks at the easily visible Black-and-Red Broadbill nests that were surveyed along the Kinabatangan river in eastern Sabah, Malaysian Borneo, and answers the following questions: (i) what is the current density of the population of the Black-and-Red Broadbill between Batu Putih and Bilit, along the Kinabatangan river, (ii) is the abundance of nests correlated with the surrounding habitat type (forest or disturbed area), and (iii) do Black-and-Red Broadbills need and/or use the riparian zone at the riverbank for nesting sites. During this study, a 55.6 kilometre river transect was surveyed for 3 days, and nests that were found were recorded. This study found that Black-and-Red Broadbills nests were significantly more often located in areas with a higher proportion of forest habitat type (compared to disturbed habitat type). Furthermore, this study shows that Black-and-Red Broadbills need branches and sticks at the river's edge to build their nest on, so they are profiting from the riparian zones along the river. Therefore we recommend enhancement of nesting opportunity by artificially providing above-water nesting sites along the river edge.

The rampant convergent and parallel evolution in shell form in the Gastropoda is well known. Many... more The rampant convergent and parallel evolution in shell form in the Gastropoda is well known. Many studies focus on the functional drivers which have been regarded as a major force in shell evolution. There is, however, a scarcity in studies that aim at understanding shell form evolution with respect to their ontogeny. Hence, we investigated the evolution of shell form in the micro-landsnail genus Plectostoma (Diplommatinidae) from the viewpoint of shell ontogeny. We examined the aperture ontogeny profiles that describe how aperture form and growth trajectory change along the shell ontogeny, and how the aperture ontogeny profiles relate to the observed shell forms. We also estimated the phylogeny of Plectostoma species, and examined patterns of character evolution for shell form. Our study revealed a general issue in the characterisation of shell shape and demonstrated how shell shape differences can be expressed as differences in the ontogeny of morphospace. It is clear that in Plectostoma the phylogenetic history does not prevent the course of shell ontogeny, and the resultant form. Finally, each species has a unique aperture ontogeny profile that determines its shell shape while retaining a conserved developmental program that maintains shell size.

PeerJ, Nov 24, 2022

Background. Asymmetric genitalia have repeatedly evolved in animals, yet the underlying causes fo... more Background. Asymmetric genitalia have repeatedly evolved in animals, yet the underlying causes for their evolution are mostly unknown. The fruit fly Drosophila pachea has asymmetric external genitalia and an asymmetric phallus with a right-sided phallotrema (opening for sperm release). The complex of female and male genitalia is asymmetrically twisted during copulation and males adopt a right-sided copulation posture on top of the female. We wished to investigate if asymmetric male genital morphology and a twisted gentitalia complex may be associated with differential allocation of sperm into female sperm storage organs. Methods. We examined the internal complex of female and male reproductive organs by micro-computed tomography and synchrotron X-ray tomography before, during and after copulation. In addition, we monitored sperm aggregation states and timing of sperm transfer during copulation by premature interruption of copulation at different time-points. Results. The asymmetric phallus is located at the most caudal end of the female abdomen during copulation. The female reproductive tract, in particular the oviduct, rearranges during copulation. It is narrow in virgin females and forms a broad vesicle at 20 min after the start of copulation. Sperm transfer into female sperm storage organs (spermathecae) was only in a minority of examined copulation trials (13 / 64). Also, we found that sperm was mainly transferred early, at 2-4 min after the start of copulation. We did not detect a particular pattern of sperm allocation in the left or right spermathecae. Sperm adopted a granular or filamentous aggregation state in the female uterus and spermathecae, respectively. Discussion. No evidence for asymmetric sperm deposition was identified that could be associated with asymmetric genital morphology or twisted complexing of genitalia. Male genital asymmetry may potentially have evolved as a consequence of a complex internal alignment of reproductive organs during copulation in order to optimize low sperm transfer rates.

Biological Journal of The Linnean Society, Aug 1, 1994

Parapatric, morphologically characterized forms of the Mediterranean snail genus Albinaria have t... more Parapatric, morphologically characterized forms of the Mediterranean snail genus Albinaria have traditionally been regarded as biological species. Recently, this view has been challenged on the basis of small interspecific genetic distances and cross-breeding experiments. In order to test whether traditionally recognized species are reproductively isolated lineages, two cases of syntopy were analysed by means of isozyme electrophoresis. The data suggest that complete reproductive isolation is present. In one of the two cases, ecological differentiation on a small spatial scale was observed.

Journal of Molluscan Studies, Jun 10, 2020

Journal of Fungi, Dec 12, 2020

Parasitism is one of the most diverse and abundant modes of life, and of great ecological and evo... more Parasitism is one of the most diverse and abundant modes of life, and of great ecological and evolutionary importance. Notwithstanding, large groups of parasites remain relatively understudied. One particularly unique form of parasitism is hyperparasitism, where a parasite is parasitized itself. Bats (Chiroptera) may be parasitized by bat flies (Diptera: Hippoboscoidea), obligate blood-sucking parasites, which in turn may be parasitized by hyperparasitic fungi, Laboulbeniales (Ascomycota: Laboulbeniomycetes). In this study, we present the global tritrophic associations among species within these groups and analyze their host specificity patterns. Bats, bat flies, and Laboulbeniales fungi are shown to form complex networks, and sixteen new associations are revealed. Bat flies are highly host-specific compared to Laboulbeniales. We discuss possible future avenues of study with regard to the dispersal of the fungi, abiotic factors influencing the parasite prevalence, and ecomorphology of the bat fly parasites.

Journal of Zoological Systematics and Evolutionary Research, May 10, 2011

The vertiginid species Gyliotrachela hungerfordiana, an obligate limestone-dwelling microsnail, i... more The vertiginid species Gyliotrachela hungerfordiana, an obligate limestone-dwelling microsnail, is relatively widespread and is found on a large number of isolated limestone hills in Peninsular Malaysia. To elucidate the pattern of colonization of these hills, we conducted a molecular phylogenetic analysis on G. hungerfordiana subpopulations from 15 separate limestone outcrops. As outgroups, we also included five related Peninsular Malaysian Vertiginidae (Gyliotrachela frequens, Gyliotrachela transitans, Gyliotrachela salpinx, Gyliotrachela depressispira and Paraboysidia tarutao), one population each. A combined analysis of nuclear (internal transcribed spacer 1) and mitochondrial (cytochrome c oxidase 1) sequences showed that (1) G. hungerfordiana is monophyletic; (2) there is a clear geographical pattern in the phylogenetic relationships between G. hungerfordiana populations, with genetic distances increasing with geographic distance; (3) this pattern is disturbed by a few longdistance (north-west to southeast and north to south) colonizations.

BMC Evolutionary Biology, Sep 1, 2016

Background: Multiple animal species exhibit morphological asymmetries in male genitalia. In insec... more Background: Multiple animal species exhibit morphological asymmetries in male genitalia. In insects, left-right genital asymmetries evolved many times independently and have been proposed to appear in response to changes in mating position. However, little is known about the relationship between mating position and the interaction of male and female genitalia during mating, and functional analyses of asymmetric morphologies in genitalia are virtually non-existent. We investigated the relationship between mating position, asymmetric genital morphology and genital coupling in the fruit fly Drosophila pachea, in which males possess an asymmetric pair of external genital lobes and mate in an unusual right-sided position on top of the female. Results: We examined D. pachea copulation by video recording and by scanning electron microscopy of genital complexes. We observed that the interlocking of male and female genital organs in D. pachea is remarkably different from genital coupling in the well-studied D. melanogaster. In D. pachea, the female oviscapt valves are asymmetrically twisted during copulation. The male's asymmetric lobes tightly grasp the female's abdomen in an asymmetric 'locking' position, with the left and right lobes contacting different female structures. The male anal plates, which grasp the female genitalia in D. melanogaster, do not contact the female in D. pachea. Experimental lobe amputation by micro-surgery and laser-ablation of lobe bristles led to aberrant coupling of genitalia and variable mating positions, in which the male was tilted towards the right side of the female. Conclusion: We describe, for the first time, how the mating position depends on coupling of male and female genitalia in a species with asymmetric genitalia and one-sided mating position. Our results show that D. pachea asymmetric epandrial lobes do not act as a compensatory mechanism for the change from symmetric to one-sided mating position that occurred during evolution of D. pachea's ancestors, but as holding devices with distinct specialized functions on the left and right sides.

PeerJ, Jul 26, 2019

Background: The heterogeneous nature of environmental DNA (eDNA) and its effects on species detec... more Background: The heterogeneous nature of environmental DNA (eDNA) and its effects on species detection and community composition estimates has been highlighted in several studies in the past decades. Mostly in the context of spatial distribution over large areas, in fewer occasions looking at spatial distribution within a single body of water. Temporal variation of eDNA, similarly, has mostly been studied as seasonality, observing changes over large periods of time, and often only for small groups of organisms such as fish and amphibians. Methods: We analyzed and compared small-scale spatial and temporal variation by sampling eDNA from two small, isolated dune lakes for 20 consecutive weeks. Metabarcoding was performed on the samples using generic COI primers. Molecular operational taxonomic unit (MOTUs) were used to assess dissimilarities between spatial and temporal replicates. Results: Our results show large differences between samples taken within one lake at one point in time, but also expose the large differences between temporal replicates, even those taken only 1 week apart. Furthermore, between-site dissimilarities showed a linear correlation with time frame, indicating that between-site differences will be inflated when samples are taken over a period of time. We also assessed the effects of PCR replicates and processing strategies on general patterns of dissimilarity between samples. While more inclusive PCR replicate strategies lead to higher richness estimations, dissimilarity patterns between samples did not significantly change. Conclusions: We conclude that the dissimilarity of temporal replicates at a 1 week interval is comparable to that of spatial replicate samples. It increases, however, for larger time intervals, which suggests that population turnover effects can be stronger than community heterogeneity. Spatial replicates alone may not be enough for optimal recovery of taxonomic diversity, and cross-comparisons of different locations are susceptible to inflated dissimilarities when performed over larger time intervals. Many of the observed MOTUs could be classified as either phyto-or zooplankton, two groups that have gained traction in recent years as potential novel bio-indicator species. Our results, however, indicate that these groups might be susceptible to large community shifts in relatively short periods of time, highlighting the need to take temporal variations into consideration when assessing their usability as water quality indicators.

Heredity, Sep 1, 1998

Symbionts of the genus Wolbachia, which cause reproductive alterations in insects, are suspected ... more Symbionts of the genus Wolbachia, which cause reproductive alterations in insects, are suspected to pass regularly from one host lineage to another. One possible route for such 'horizontal transmission' is via parasitization. Here, we study this hypothesis in a complex guild of specialized parasitoids and inquilines, associated with the parthenogenetic, Wolbachia-infected gall wasp Diplolepis rosae. Diplolepis rosae galls ('bedeguar galls') were collected at three localities in The Netherlands and Germany. Specimens of most guild members were obtained. Using molecular techniques, the presence of Wolbachia was detected in five members of the assemblage. Three of these, Torymus bedeguaris, Habrocytus bedeguaris and D. rosae carried a Wolbachia belonging to the same subgroup (type I). A phylogenetic analysis was performed on DNA sequences from the FtsZ gene from these three Wolbachias. The analysis showed that the three strains do not cluster closely together, which indicates that the parasitoids have not acquired their Wolbachia from their host. We could not detect host-to-parasitoid transmission in this assemblage (where interactions are both specific, frequent, and possibly ancient).

The characteristic ground colour and banding patterns on shells of the land snail Cepaea nemorali... more The characteristic ground colour and banding patterns on shells of the land snail Cepaea nemoralis form a classic study system for genetics and adaptation as it varies widely between individuals. We use RNAseq analysis to identify candidate genes underlying this polymorphism. We sequenced cDNA from the foot and the mantle (the shellproducing tissue) of four individuals of two phenotypes and produced a de novo transcriptome of 147,397 contigs. Differential expression analysis identified a set of 1,961 transcripts that were upregulated in mantle tissue. Sequence variant analysis resulted in a set of 2,592 transcripts with single nucleotide polymorphisms (SNPs) that differed consistently between the phenotypes. Inspection of the overlap between the differential expression analysis and SNP analysis yielded a set of 197 candidate transcripts, of which 38 were annotated. Four of these transcripts are thought to be involved in production of the shell's nacreous layer. Comparison with morphassociated Restriction-site Associated DNA (RAD)-tags from a published study yielded eight transcripts that were annotated as metallothionein, a protein that is thought to inhibit the production of melanin in melanocytes. These results thus provide an excellent starting point for the elucidation of the genetic regulation of the Cepaea nemoralis shell colour polymorphism.

Entomologische Berichten, 1983

Veliger, Oct 1, 2008

We redescribe and figure Valiguna flava, an almost unknown Southeast-Asian land slug. Detailed mo... more We redescribe and figure Valiguna flava, an almost unknown Southeast-Asian land slug. Detailed morphology, radula, jaw and living specimens of Valiguna flava were studied for the first time, based on material recently collected in Borneo and on the holotype. Vl. flava is also compared with Valiguna siamensis, the only other species of the genus, which is for the first time recorded in China

Biology Open, 2017

Insect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved i... more Insect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved in some groups, presumably as a result of postmating sexual selection. To increase our understanding of this phenomenon, we studied the function of one such structure. The male genitalia of Callosobruchus subinnotatus (Coleoptera: Bruchinae) contain a pair of jaw-like structures with unknown function. Here, we used phenotypic engineering to ablate the teeth on these jaws. We then experimentally assessed the effects of ablation of the genital jaws on mating duration, ejaculate weight, male fertilization success and female fecundity, using a double-mating experimental design. We predicted that copulatory wounding in females should be positively related to male fertilization success; however, we found no significant correlation between genital tract scarring in females and male fertilization success. Male fertilization success was, however, positively related to the amount of ejaculate transferred by males and negatively related to female ejaculate dumping. Ablation of male genital jaws did not affect male relative fertilization success but resulted in a reduction in female egg production. Our results suggest that postmating sexual selection in males indeed favors these genital jaws, not primarily through an elevated relative success in sperm competition but by increasing female egg production.

Current Opinion in Genetics & Development, Aug 1, 2021

Recent technical innovations are revealing surprising patterns in mollusc shell pigmentation, suc... more Recent technical innovations are revealing surprising patterns in mollusc shell pigmentation, such as an unexpectedly modest role for melanins and rapid divergences in the mix of pigments used to achieve similar colour patterns. The elucidation of the molecular genetic basis of shell pigmentation has been slow, probably because of the high genome complexity of gastropods and bivalves. Recent work within the old field of evolutionary ecology of shell pigmentation allows a greater role for the analysis of large-geographic-scale patterns (sometimes employing citizen-science data), as well as experimental field studies. However, the field remains dominated by land snails as model organisms, while colour pattern evolution in marine gastropods and bivalves, particularly those not exposed to visual predators, remains mysterious.

PeerJ, Apr 1, 2014

Predator-prey interactions are among the main ecological interactions that shape the diversity of... more Predator-prey interactions are among the main ecological interactions that shape the diversity of biological form. In many cases, the evolution of the mollusc shell form is presumably driven by predation. However, the adaptive significance of several uncommon, yet striking, shell traits of land snails are still poorly known. These include the distorted coiled "tuba" and the protruded radial ribs that can be found in micro-landsnails of the genus Plectostoma. Here, we experimentally tested whether these shell traits may act as defensive adaptations against predators. We characterised and quantified the possible anti-predation behaviour and shell traits of Plectostoma snails both in terms of their properties and efficiencies in defending against the Atopos slug predatory strategies, namely, shell-apertural entry and shell-drilling. The results showed that Atopos slugs would first attack the snail by shell-apertural entry, and, should this fail, shift to the energetically more costly shell-drilling strategy. We found that the shell tuba of Plectostoma snails is an effective defensive trait against shell-apertural entry attack. None of the snail traits, such as resting behaviour, shell thickness, shell tuba shape, shell rib density and intensity can fully protect the snail from the slug's shell-drilling attack. However, these traits could increase the predation costs to the slug. Further analysis on the shell traits revealed that the lack of effectiveness in these anti-predation shell traits may be caused by a functional trade-off between shell traits under selection of two different predatory strategies.