The karstic caves of the Meuse River Basin in Belgium preserve nearly 200 collective burials dating to the late Neolithic period. Among these, the cave burials of Hastière Caverne M, Sclaigneaux, Bois Madame and Maurenne Caverne de la Cave are represented by numerous individuals and radio-carbon dated to circa 4,635 to 3,830 years B.P. Dental casts from mandibular and maxillary deciduous molars are scored using multiple methods to provide a regional overview of the prevalence and expres-sion of deciduous molar crown traits, and to compare frequencies between cave burial sites with a focus on temporal differentiation. Carabelli’s trait varies from a small pit to a full cusp, the largest of which are found at Hastière Caverne M. The hypoconulid ranges from moderately large to very large. A meta-conulid is absent or small. Although the results are contingent on idiosyncratic preservation, differences in the frequencies of expression of Carabelli’s trait, a pronounced hypoconulid, and the presence of a metaconule and protostylid separate the earlier cave burial at Hastière Caverne M from the final/late Neolithic sites of Sclaigneaux and Bois Madame.
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RBINS Staff Publications 2018
Abstract The defense strategy of an insect toward natural enemies can include a trait that appears at first sight to contradict its defensive function. We explored phylogeny, chemistry, and defense efficiency of a peculiar group of hymenopteran sawfly larvae where this contradiction is obvious. Pseudodineurini larvae live in leaf mines that protect them from some enemies. Disturbed larvae also emit a clearly perceptible lemon-like odor produced by ventral glands, although the mine hampers the evaporation of the secretion. The mine could also lead to autointoxication of a larva by its own emitted volatiles. Citral was the major component in all Pseudodineurini species, and it efficiently repels ants. We conclude that full-grown larvae that leave their mine to pupate in the soil benefit from citral by avoiding attacks from ground-dwelling arthropods such as ants. In some species, we also detected biosynthetically related compounds, two 8-oxocitral diastereomers (i.e., (2E,6E)- and (2E,6Z)-2,6-dimethylocta-2,6-dienedial). Synthetic 8-oxocitral proved to be a potent fungicide, but not an ant repellent. The discrete distribution of 8-oxocitral was unrelated to species grouping in the phylogenetic tree. In contrast, we discovered that its presence was associated with species from humid and cold zones but absent in species favoring warm and dry environments. The former should be protected by 8-oxocitral when faced with a fungal infestation while crawling into the soil. Our work shows the importance of integrating knowledge about behavior, morphology, and life history stages for understanding the complex evolution of insects and especially their defense strategies.
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