Male and female reproductive success in natural and anthropogenic populations of Malaxis monophyllos (L.) Sw. (Orchidaceae)

In the presented study, male and female reproductive success was analyzed in relation to the population size, floral display and pollinators’ availability in natural and anthropogenic populations of the orchid Malaxis monophyllos (L.) Sw. Our results indicated significant differences between all investigated populations in parameters of floral display, including heights and number of flowers per inflorescence, as well the number of flowering individuals and their spatial structure. Additionally, populations differed both in male (pollinia removal) and female (fruit set) reproductive success, but only the fruit set clearly differentiated anthropogenic and natural populations. Despite the average flower number per plant being significantly higher in two of the anthropogenic populations, it was not related to the fruits set, which was significantly lower there. Moreover, our preliminary study concerning the potential pollinators of M. monophyllos showed a higher contribution of flies in natural habitats than in anthropogenic ones. Thus, we can suspect that the main factors influencing the level of female reproductive success in M. monophyllos populations are abundance of effective pollinators, as well as flower visitors, which may have resulted in a different level of pollen discounting in populations. Therefore, further studies concerning breeding system and pollination as important forces that shape demographic processes in M. monophyllos populations are necessary. Our results also indicate that suitable conservation methods in M. monophyllos should always include the preservation of potential pollinators, especially in these new, secondary habitats

What keeps "living dead" alive : demography of a small and isolated population of Maculinea (= Phengaris) alcon

Small and isolated populations are prone to future extinctions and thus perceived as living dead'. Although generally considered to be of low conservation value, their existence can still enhance species survival at the landscape scale through improving the connectivity of other populations and facilitating some (even if little) gene flow. We investigated the demography and genetic status of a tiny and highly isolated local population of Maculinea (=Phengaris) alcon near its distribution margin with the aim of identifying the features that allow it to persist. The study comprised intensive mark-recapture, surveys of Gentiana pneumonanthe foodplants and butterfly eggs laid on them, as well as genetic analyses. The population has been found to be characterised by low genetic diversity and estimated at only a few tens of individuals. The foodplant availability turned out to be the most obvious factor limiting M. alcon abundance. Nevertheless, the life expectancy of adult butterflies is fairly long, and their flight period very short, implying that most individuals occur within the same time window. Together with the relatively little protandry observed, i.e. almost synchronous emergence of males and females, this increases the chances of random mating among the individuals. Moreover, the butterflies move freely across the core habitat fragment. All things concerned, the effective population size is presumably not much lower than the recorded population size. Our findings provide guidelines for pinpointing those among "living dead" populations that are likely to be the most persistent and thus worth conservation efforts aimed at preserving them

The first record of the genus Phytodietus Gravenhorst, 1829 (Hymenoptera: Ichneumonidae: Tryphoninae) in Papua New Guinea, with description of a new species

AbstractThe genus Phytodietus Gravenhorst, 1829 is recorded from Papua New Guinea for the first time, based on a newly described species, P. (P.) guineus sp. nov. An identification key to the Australasian Phytodietus species is provided.http://zoobank.org/urn:lsid:zoobank.org:pub:D23507BB-F353-4CDE-AB12-2B1DBD4B5F2

The genus Phytodietus Gravenhorst, 1829 (Hymenoptera, Ichneumonidae Tryphoninae) in Kenya, with the description of a new species

Varga, Oleksandr, Kostro-Ambroziak, Agata (2020): The genus Phytodietus Gravenhorst, 1829 (Hymenoptera, Ichneumonidae Tryphoninae) in Kenya, with the description of a new species. Zootaxa 4778 (1): 196-200, DOI: https://doi.org/10.11646/zootaxa.4778.1.

First report of the genus Phytodietus Gravenhorst, 1829 (Hymenoptera: Ichneumonidae: Tryphoninae) from Thailand

Figure 5a - Phytodietus pitambari: head, facial view

A new species of Phytodietus Gravenhorst, 1829 (Hymenoptera: Ichneumonidae: Tryphoninae) from China

Kostro-Ambroziak, Agata, Zhou, Zichen, Reshchikov, Alexey (2020): A new species of Phytodietus Gravenhorst, 1829 (Hymenoptera: Ichneumonidae: Tryphoninae) from China. Zootaxa 4877 (2): 391-395, DOI: https://doi.org/10.11646/zootaxa.4877.2.1

A broad spectrum of host plant responses to the actions of the gall midge: case study of Robinia pseudoacacia L. and Obolodiplosis robiniae (Haldeman)

Abstract This study aims to provide insights into plant-insect interaction during the formation and development of open gall structure on the leaves of Robinia pseudoacacia during gall formation by Obolodiplosis robiniae. This was the first time such far-reaching studies were performed at a biochemical and anatomical level. The gall wall is created from a few thick cells covered with epidermis. This parenchymatous nutritive tissue is rich in starch. Sclerenchyma only occurs around the vascular bundles as a result of the lignification of the parenchyma of the bundle sheaths. The level of reactive oxygen species (ROS) in the new structure was reduced and catalase activity was inhibited, which suggests another pathway of ROS decomposition – e.g. by ascorbate or glutathione peroxidase. The gall structure was combined with an increasing level of protein and non-protein thiols. Phenols seems to be a good protective factor; whose level was lower in infected leaflets. Levels of MUFA (monosaturated fatty acids) and SFA (saturated fatty acids) rose, probably as source of food for insects. The amount of fatty acid is positively correlated with the plant response. We detected that non infected leaflets produced C6:0 (hexanoic acid) and C8:0 (octanoic acid) fatty acids connected with odor. Changes in gall color as they develop are connected with photosynthetic pigments degradation (mainly chlorophylls) where the pathway of astaxanthin transformation to fatty acid is considered to be the most important process during gall maturation. Nutritive tissue is composed mainly of octadecanoic acid (C18:0) – a main source of food for O. robiniae

Table_1_Two lines of defense in the pupas of ichneumonid wasp parasitoids associated with spider hosts.DOCX

Insects in the pupal stage are vulnerable to various predators because the pupa is immobile. The pupas of parasitoid ichneumonid wasps (Ichneumonidae) associated with spider hosts have evolved two lines of defense against predators, namely a cocoon spun by the parasitoid larva and a web provided by the spider host. The web is derived from a normal or modified spider web built by the spider under manipulation by the penultimate instar of the parasitoid wasp. In laboratory experiments, we tested the efficacy of these two defensive lines using six potential predators with two different types of mouthparts coming from three foraging guilds. The presence of the cocoon significantly reduced predation. Scavengers with chewing mouthparts, e.g., cockroaches and crickets, attacked and consumed pupas within both sparse and strong cocoon walls. Scavengers with piercing mouthparts were able to attack pupas in cocoons with a sparse wall, but not with a strong wall. Collectors and true predators showed no interest in cocoons. The presence of a web increased pupa protection by up to 80% when the web was on the ground and by up to 95% when the web was in the air. Only scavengers with chewing mouthparts were able to reach and consume pupas sheltered by the web. We provide the first evidence of how the two lines of defense contribute to parasitoid defense during the pupal stage.</p

The floral signals of the inconspicuous orchid Malaxis monophyllos : how to lure small pollinators in an abundant environment

SIMPLE SUMMARY: Malaxis monophyllos is an ephemeral orchid with very small, greenish flowers, whose pollination system remains vague. Therefore, the authors aimed to identify the flower’s features, including its anatomical micro and ultrastructure as well as scent biochemistry, which are involved in attracting pollinators. In this paper, the authors established the variety of emissions of M. monophyllos volatile compounds, with a high proportion of aldehydes and aliphatic alcohols, listed as chemicals that induce a pronounced reaction in Diptera. Second, the entire M. monophyllos labellum exhibits metabolic and secretory activity, which can be related to both emission of volatiles and visual attractants but also to the nutritional reward for pollinators. All these flower features indicated that its pollination system is dedicated to dipterans, with few signaling modalities corresponding to deceptive species (brood site and food decoy) but also referring to rewarding ones (nutritional secretion, fungus/microbe reward). This research reveals a few new issues in M. monophyllos pollination biology that provides new scientific areas for in-depth insights in the future. ABSTRACT: Many orchid species have evolved complex floral signals to ensure pollination efficiency. Here, the authors combined analyses of anatomical flower structure with analyses of the volatile composition and flower-visiting insects’ behaviour, as well as characterised features that can attract pollinators of the inconspicuous orchid Malaxis monophyllos. During field observations, the authors found that only small Diptera (e.g., mosquitos, drosophilids, fungus gnats) visit and are interested in the flowers of M. monophyllos, which was reflected in the characterised flower features that combine well with the pollination system, which engages dipterans. Analyses of the M. monophyllos floral scent revealed substantial concentrations of aliphatic compounds, e.g., 1-octen-3-ol and 1-octanol, which condition the mushroom-like scent and a substantial fraction of alkanes, some of which have been previously described as sex mimicry and aggregation pheromones in orchids’ deceptive systems. The labellum anatomical structure exhibits a highly diverse cell cuticle surface and pronounced metabolic and secretory activity of the epidermal and subepidermal cells from all parts of the labellum. Moreover, our study provides evidence for the subsequent decoys of M. monophyllos flowers, including visual signals, such as raphides located on the labellum margin and the rewarding ones connected with lipid secretion limited to the area behind the column. Taking an integrative approach to studying M. monophyllos pollination biology, the authors provide new insight into its previously vague pollination strategies and provide evidence for complex floral signal operation in luring potential pollinators. The synergistic effect of M. monophyllos flowers’ volatile and visual signals, together with additional rewarding for nectar/fungus/microbe-feeding pollinators, requires further detailed investigation that will be invaluable in explaining the evolution of Diptera-specific pollination systems in orchids