Effects of Flower-Enriched Ecological Focus Areas on Functional Diversity Across Scales

Ecological Focus Areas (EFAs) to benefit biodiversity became mandatory in intensively farmed landscapes after the reform of the European Common Agricultural Policy (CAP) in 2013. The implementation of EFAs as uncropped field margins has been criticized as ineffective but created a window of opportunity to test if augmenting them with annual flower strips can benefit biodiversity. In this study, we investigated if annual flower strips on EFAs benefited functional biodiversity in intensively farmed landscapes. To this end we established eleven annual flower strips with a seed mixture targeted for both natural enemies and pollinators, on areas were farmers had planned for EFAs. We determined effects on aphids and their natural enemies in cereal fields close to six of the flower strips, and for solitary bees and wasp close to and in the surroundings of all eleven flower strips. We found that annual flower strips benefited the abundance of hoverfly larvae and possibly also that of solitary bees. However, there were neither any significant effects on natural enemies (other than hoverfly larvae), nor any difference in natural pest control as shown by lack of differences in aphid numbers and parazitation rates. Abundances of solitary bees and wasps in the surrounding landscapes were unaffected, although there was a tendency for more solitary bee cells closer to the strips. We suggest that the critical issue leading to the mostly negative results is the lack of permanent structures to sustain populations of arthropods that in turn can benefit from annual flower strips. Hence, future agri-environmental policies need to carefully consider if and how annual agri-environmental measures should be implemented in intensively managed agricultural landscapes, e.g., by combining them with more permanent structures.

Landscape Simplification Modifies Trap-Nesting Bee and Wasp Communities in the Subtropics

(1) Background: Landscape simplification is a major threat to bee and wasp conservation in the tropics, but reliable, long-term population data are lacking. We investigated how community composition, diversity, and abundance of tropical solitary bees and wasps change with landscape simplification (plant diversity, plant richness, distance from forest, forest cover, and land use type) and season. (2) Methods: We installed 336 timber and cob trap nests in four complex forests and three simplified orchards within the subtropical biodiversity hotspot of south-east Queensland, Australia. Trap nests were replaced every season for 23 months and all emergents identified. (3) Results: We identified 28 wasp species and 13 bee species from 2251 brood cells. Bee and wasp community composition changed with landscape simplification such that large, ground-nesting, and spider-hunting species were present in all landscapes, while those with specialist resource requirements and (clepto) parasitoids were present only in complex landscapes. Abundance and diversity of bees and wasps were unaffected by landscape simplification but increased with rainfall. (4) Conclusions: This study highlights the need for multi-year studies incorporating nuanced measures such as composition with a focus on functional diversity to detect changes bee and wasp populations.

Height differences in clonal stands of Tussilago farfara promote outcrossing by influencing pollinator behaviour

Plants with mixed mating systems balance the advantages of selfing and the costs of inbreeding. Previous studies have shown that plant species with the ability to self-pollinate and cross pollinate have strategies to promote outcrossing to increase genetic diversity. Various features of floral morphology are thought to be deliberate mechanisms to manipulate plant mating systems. I hypothesized that within-plant variation in flower stem height is a morphological trait that can reduce geitonogamy by increasing pollinator movement among plants. This hypothesis was tested using coltsfoot (Tussilago farfara); coltsfoot plants host several flowering stems that differ in height, with each stem having a single, terminal flowerhead. I used cut flowers to create ‘populations’ of coltsfoot in which each plant had four inflorescences with equal or unequal flower stalk lengths and measured frequency of insect pollinators that would stay among flowers within a plant or move to other plants. All pollinators (bee flies, hover flies, solitary bees and wasps) showed a marked discrimination in favor of leaving plants with flowers of different heights and stayed when plants had flowers of the same height. This study shows that variation in flower heights is important for reducing geitonogamy in coltsfoot and suggests that the evolution of this morphological trait should be considered in studies of mating systems.

Phylogeny and divergence estimates for the gasteruptiid wasps (Hymenoptera : Evanioidea) reveals a correlation with hosts

The Gasteruptiidae are an easily recognised family of wasps whose larvae are considered predator-inquilines in the nests of solitary bees and wasps. There has been minimal molecular research on the family and as a result little understanding of the evolutionary relationships within the group. We present the first molecular phylogeny focused on Gasteruptiidae, generated using three molecular fragments (mitochondrial C01 and nuclear markers EF1-α and 28s) and estimate the divergence times of Evanioidea based on three secondary calibration points. The analyses included 142 specimens of Gasteruptiidae and 5 outgroup taxa from Aulacidae and Evaniidae. The monophyly of the Gasteruptiidae and its subfamilies Gasteruptiinae (Gasteruption) and Hyptiogastrinae (Hyptiogaster and Pseudofoenus) are confirmed. Our results indicate that Evanioidea diverged during the late Jurassic at 151.3 (171.99–136.15)Ma with Evaniidae during the early Cretaceous at 137.33 (140.86–133.67)Ma, and Gasteruptiidae during the Palaeocene at 60.23 (83.78–40.02)Ma. The crown age of Hyptiogastrinae was estimated to be during the mid-Eocene 40.72 (60.9–22.57)Ma and for Gasteruption during the early Eocene at 47.46 (64.7–31.75)Ma, which corresponded to their host divergence ages. We anticipate that more extensive taxon sampling combined with the use of phylogenomic data will help resolve low support within the Gasteruption clade.

Four new species of Australian velvet ants (Hymenoptera: Mutillidae, Aglaotilla) reared from bee and wasp nests, with a review of Australian mutillid host records

Four species of velvet ants (Mutillidae) were reared from nests of solitary bees and wasps collected using trap nests in southwest Australia and identified using morphological and DNA barcoding approaches. All four species, Aglaotilla micra sp. nov., A. lathronymphos sp. nov., A. chalcea sp. nov. and A. schadophaga sp. nov., are described as new, the last three from both sexes. A. micra, A. lathronymphos and A. chalcea are parasitoids of wasps in the genera Pison and Aulacophilinus (Crabronidae), with A. chalcea also recorded from Paralastor (Vespidae). Aglaotilla schadophaga is a parasitoid of bees in the genus Megachile (Megachilidae). The biologies and known hosts of Australian Mutillidae are reviewed. Photographs are also provided of type material for Ephutomorpha aeneidorsis Turner, 1914 (=Aglaotilla discolor Brothers, 2018), Mutilla metallica Smith, 1855 and Ephutomorpha subelegans Rayment, 1933. The lectotype of E. subelegans is formally designated.

Sleeping aggregation of an oil-collecting bee, Centris (Paracentris) xanthomelaena Moure & Castro (Hymenoptera: Apidae: Centridini)

Sleep aggregations have been registered for some species of solitary bees and wasps. In this note we describe the aggregation behaviour of Centris xanthomelaena Moure & Castro bees in their inactive periods. The dormitories were discovered close to the bee nesting sites, in a Caatinga area. We monitored the males and females at the sleeping site for 16 consecutive days in July 2017. We observed that females of C. xanthomelaena spent the night outside their nests, indry branches of Mimosa tenuifl ora (Fabaceae). Furthermore, males and females have shared the dormitories, and sometimes they formed mixed ones. Both males and females fl ew around the nearest dormitories during all observation days. The data about the sleep behaviour of C. xanthomelaena will contribute to the understanding of these aspects within the Centris genus.