Eske De Crop

Importance of autonomous selfing is inversely related to population size and pollinator availability in a monocarpic plant

PREMISE OF THE STUDY In animal-pollinated plants, autonomous selfing may provide reproductive assurance when pollinators or reproductive partners are limited. Under such circumstances, the contribution of pollinator-mediated seed set to total seed production also may be more variable compared with situations in which pollinator abundances are high or populations consist of large numbers of individuals. Despite the widespread acceptance of the reproductive assurance hypothesis, only limited empirical evidence exists that autonomous selfing confers reproductive output and guarantees constant seed set under variable pollination environments. METHODS We performed emasculation experiments in 22 populations of the short-lived, monocarpic plant Centaurium erythraea in a fragmented dune landscape. KEY RESULTS Floral emasculations resulted in a significantly lower seed set compared with that of intact flowers. Seed set in emasculated flowers also declined significantly with decreasing population size and pollinator availability, whereas seed set of intact flowers did not depend on population size nor on pollinator availability. Variability in seed set among individuals was significantly lower in intact than in emasculated flowers and decreased significantly with increasing population size when flowers were emasculated but not in intact flowers. CONCLUSIONS These results indicate that pollinator-mediated seed set is strongly dependent both on population size and on pollinator availability but that reproductive assurance through autonomous selfing guarantees relatively constant levels of total seed production, even when populations are small and/or pollinator limited. High variation in seed set of emasculated flowers suggests strong unpredictability in pollinator services in small populations.

New combinations in Lactifluus. 3. L. subgenera Lactifluus and Piperati

In this last of a series of three papers, new combinations in the genus Lactifluus are proposed. This paper treats Lactifluus subg. Lactifluus (an autonymous subgenus) and Lactifluus subg. Piperati (proposed as a new subgenus). In Lactifluus subg. Lactifluus, six sections are recognized (five of them as new combinations) and 46 new combinations are proposed at species level. In Lactifluus subg. Piperati, two sections are recognized (as new combinations) and nine new species combinations are proposed. In addition, new combinations are proposed for an unassigned section and its single species as well as for three unassigned species.

Untangling the Central African Cantharellus Sect. Tenues: Cantharellus minutissimus sp. nov. and Epitypification of Cantharellus alboroseus

Abstract Cantharellus section Tenues was originally created for four new, very small, redorange-yellow Central African chanterelles with a more or less fistulose stipe, short basidia and an omphaloid habit. The type species, C. tenuis, is here considered unrelated to the other three species as it is the only species having clamp connections. All four species remain poorly known and need to be recollected and epitypified with recently collected, sequenced specimens that comply to the original description. In this paper, C. alboroseus is epitypified, and an equally small species, C. minutissimus, is introduced. Both species are systematically placed using a multigene phylogeny.

Lactifluus volemus in Europe: Three species in one--Revealed by a multilocus genealogical approach, Bayesian species delimitation and morphology.

This study provides morphological and molecular evidence (from nuclear ITS, LSU, and rpb2 DNA sequences) for three previously unrecognized species within the morphospecies Lactifluus volemus from Europe. Phylogenetic species are supported by both a multi-locus tree-based method and Bayesian species delimitation. Lactifluus volemus and Lactifluus oedematopus are provided with a new description, and a third species, Lactifluus subvolemus, is described as new to science. Lactifluus oedematopus can be easily recognized by its short pileipellis hairs. Both L. volemus and L. subvolemus have longer pileipellis hairs and can only be distinguished from each other based on cap colour. Intermediary colour forms, however, occur as well, and cannot be identified as either L. volemus or L. subvolemus without molecular data. Revealing that L. volemus--already considered extinct in the Netherlands and the Belgian Flemish region, and declining in other European countries--is actually a complex of three species that are even more vulnerable to extinction, this study emphasizes the fundamental role of taxonomy in species conservation.

Lactarius subgenus Russularia (Basidiomycota, Russulales): novel Asian species, worldwide phylogeny and evolutionary relationships

Lactarius subg. Russularia is a large group of milkcaps occurring almost worldwide and dominant in many ecosystems. In this study we focus on new diversity, evolutionary relationships, divergence time, and origin of the subgenus. Six conifer symbionts are described as new to science: Lactarius atrii, L. aurantionitidus, L. dombangensis, L. flavigalactus, L. lachungensis, and L. sikkimensis. Species delimitation is assessed based on the concordance between morphological characteristics and an ITS phylogeny. Infrageneric relationships were studied using a phylogeny constructed from concatenated ITS-rpb2 data using Maximum Likelihood and Bayesian inference. Results show that species in this subgenus do not cluster together according to their geographic origin. Intercontinental sister relationships between Europe/Asia/North America are common but actual conspecificity is rare. This result suggests that allopatric speciation has played an important role within this subgenus. Only few morphological characteristics tend to be phylogenetically informative, with the most important being presence or absence of true cystidia and the pileipellis structure. Two datasets were generated in order to estimate the age of L. subg. Russularia. The results suggest the origin of L. subg. Russularia to be in the Mid Miocene period.

The impact of habitat fragmentation on the interaction between Centaurium erythraea (Gentianaceae) and its specialized seed predator Stenoptilia zophodactylus (Pterophoridae, Lepidoptera)

Habitat fragmentation can affect plant population characteristics and plant traits, which in turn can change biotic interactions, such as plant–insect interactions. Because of this, habitat fragmentation can affect reproductive success and survival of both the plant and seed predators, especially when the predator is rare and specialized. This study focuses on the level of fruit predation in Centaurium erythraea by its specific seed predator, the plume moth Stenoptilia zophodactylus, in a fragmented coastal dune landscape. To investigate the consequences of habitat fragmentation, we assessed the effect of population and plant characteristics of 25 C. erythraea populations on fruit predation by S. zophodactylus. Although the distribution of this specialized predator is poorly documented, our results show that S. zophodactylus occurred frequently in most of the studied C. erythraea populations. We found a strong correlation between the spatial isolation of the host plant and the level of fruit predation, with low predation in isolated populations, most likely due to the limited dispersion capacity of the plume moth. C. erythraea individuals experienced a higher risk of fruit predation when showing a large floral display size, presumably because they are more attractive. However, at fruit level, the risk of predation decreases with increasing floral display at individual plant level, representing a sort of dilution effect. Our findings indicate that maintaining and restoring large, dense and rather connected populations of C. erythraea will be beneficial for the sustainable conservation of the rare specialist seed predator S. zophodactylus, without increasing the predation pressure on the host plant.

Lactifluus kigomaensis sp. nov. from Kigoma Province,Tanzania

Abstract Lactifluus Lactifluus kigomaensis De Crop & Verbeken sp. nov. is described from primary miombo woodlands in the biologically underexplored Kigoma Province in North Western Tanzania. The species is consumed and offered for sale on local markets.

Lactifluus persicinus sp. nov. from the gallery forests of West Cameroon

During field work in the Noun division of western Cameroon during 2011, 2012, and 2014, several collections of an unknown Lactifluus species were discovered in a gallery forest with Uapaca guineensis. Molecular and morphological research shows that these collections represent a new species, Lactifluus persicinus, which is described in this paper. Lactifluus persicinus belongs to Lf. sect. Xerampelini in Lf. subg. Pseudogymnocarpi.

Novel diversity in Lactifluus section Gerardii from Asia: five new species with pleurotoid or small agaricoid basidiocarps

ABSTRACT The ectomycorrhizal milkcap genus Lactifluus (Russulaceae) is commonly found in tropical and subtropical forests of Southeast Asia. During several sampling expeditions in Thailand, multiple collections of Lactifluus (Lf.) species with pleurotoid or small agaricoid basidiocarps were found. A molecular study was combined with a morphological study, in which the collections were compared with herbarium material. The molecular study indicated that four Thai collections belonged to undescribed species within Lactifluus section Gerardii, as was also the case for herbarium collections of a pleurotoid species from Nepal. One other collection from Thailand appeared closely related to Lf. uyedae, known only from Japan. Five species are described as new in the genus: Lf. auriculiformis, Lf. gerardiellus, Lf. bhandaryi, Lf. pulchrellus, and Lf. raspei.