Cuckoo male bumblebees perform slower and longer flower visits than free-living male and worker bumblebees

Cuckoo bumblebees are a monophyletic group within the genus Bombus and social parasites of free-living bumblebees, upon which they rely to rear their offspring. Cuckoo bumblebees lack the worker caste and visit flowers primarily for their own sustenance and do not collect pollen. Although different flower-visiting behaviours can be expected between cuckoo and free-living bumblebees due to different biological constraints, no study has yet quantified such differences. Here, we provide the first empirical evidence of different flower-visiting behaviours between cuckoo and free-living bumblebees. We recorded the flower-visiting behaviour of 350 individual bumblebees over two years in a wild population of the entomophilous plant Gentiana lutea, of which they are among the main pollinators. In cuckoo bumblebees (28.9% of the total), we only found males, while we found both workers and males in free-living bumblebees. Cuckoo bumblebees visited significantly more flowers for longer time periods than both free-living bumblebee workers and males within whorls, while differences at the whole-plant level were less marked. Free-living bumblebee males visited more flowers and performed slightly longer flower visits than workers. Behavioural differences between cuckoo male bumblebees and free-living bumblebee workers are likely related to different foraging needs, while differences between cuckoo and free-living bumblebee males may be caused by differences in colony development and a delayed mating period of free-living bumblebees. The longer visits made by cuckoo male bumblebees will likely negatively affect plant reproductive success through increased within-plant pollen flow.

Ebogotermes raphaeli, new genus and new species, an African soldierless termite described from the worker caste (Isoptera, Termitidae, Apicotermitinae)

Ebogotermes raphaeli gen. n. sp. n., is described from workers collected in Cameroon. This soil-feeding termite is the largest soldierless termite from central Africa and aligns with the Anoplotermes subgroup. The enteric valve armature is weakly armed and, as with most apicotermitine species, is uniquely diagnostic.

Evidence for a conserved queen-worker genetic toolkit across slave-making ants and their ant hosts

The ecological success of social Hymenoptera (ants, bees, wasps) depends on the division of labour between the queen and workers. Each caste is highly specialized in their respective function in morphology, behaviour and life history traits, such as lifespan and fecundity. Despite strong defences against alien intruders, insect societies are vulnerable to social parasites, such as workerless inquilines or slave-making (dulotic) ants. Here, we investigate whether gene expression varies in parallel ways between slave-making ants and their host ants across five independent origins of ant slavery in the Formicoxenus-group of the ant tribe Crematogastrini. As caste differences are often less pronounced in slave-making ants than non-parasitic ants, we also compare the transcriptomes of queens and workers in these species. We demonstrate a substantial overlap in expression differences between queens and workers across taxa, irrespective of lifestyle. Caste affects the transcriptomes much more profoundly than lifestyle, as indicated by 37 times more genes being linked to caste than to lifestyle and by multiple caste-associated gene modules with strong connectivity. However, several genes and one gene module are linked to the slave-making lifestyle across the independent origins, pointing to some evolutionary convergence. Finally, we do not find evidence for an interaction between caste and lifestyle, indicating that caste differences remain consistent even when species switch to a parasitic lifestyle. Our findings are a strong indication for the existence of a core set of genes whose expression is linked to the queen and worker caste in this ant taxon, supporting the genetic-toolkit hypothesis.

Recombination mapping of the Brazilian stingless bee Frieseomelitta varia confirms high recombination rates in social hymenoptera

Background Meiotic recombination is a fundamental genetic process that shuffles allele combinations and promotes accurate segregation of chromosomes. Analyses of the ubiquitous variation of recombination rates within and across species suggest that recombination is evolving adaptively. All studied insects with advanced eusociality have shown exceptionally high recombination rates, which may represent a prominent case of adaptive evolution of recombination. However, our understanding of the relationship between social evolution and recombination rates is incomplete, partly due to lacking empirical data. Here, we present a linkage map of the monandrous, advanced eusocial Brazilian stingless bee, Frieseomelitta varia, providing the first recombination analysis in the diverse Meliponini (Hymenoptera, Apidae). Results Our linkage map includes 1417 markers in 19 linkage groups. This map spans approximately 2580 centimorgans, and comparisons to the physical genome assembly indicate that it covers more than 75 % of the 275 Megabasepairs (Mbp) F. varia genome. Thus, our study results in a genome-wide recombination rate estimate of 9.3–12.5 centimorgan per Mbp. This value is higher than estimates from nonsocial insects and comparable to other highly social species, although it does not support our prediction that monandry and strong queen-worker caste divergence of F. varia lead to even higher recombination rates than other advanced eusocial species. Conclusions Our study expands the association between elevated recombination and sociality in the order Hymenoptera and strengthens the support for the hypothesis that advanced social evolution in hymenopteran insects invariably selects for high genomic recombination rates.

Two new species of doryline ants (Hymenoptera, Formicidae) with 11-segmented antennae from India

Two new species of the subfamily Dorylinae Leach, 1815 namely Parasyscia ganeshaiahisp. nov. and Syscia indicasp. nov. are described and illustrated based on the worker caste. These species were collected in the Eaglenest Wildlife Sanctuary, Arunachal Pradesh, Northeast India. Keys to Parasyscia of India and Syscia of Asia are provided based on the worker caste.

Nuclear Translocation of Vitellogenin in the Honey Bee (Apis mellifera)

Vitellogenin (Vg) is a conserved protein used by nearly all oviparous animals to produce eggs. It is also pleiotropic and performs functions in oxidative stress resistance, immunity, and, in honey bees, behavioral development of the worker caste. It has remained enigmatic how Vg affects multiple traits. Here, we asked whether Vg enters the nucleus and acts via DNA-binding. We used immunohistology, cell fractionation and cell culturation to show that a structural subunit of honey bee Vg translocates into cell nuclei. We then demonstrated Vg-DNA binding theoretically and empirically with prediction software and chromatin immunoprecipitation with sequencing (ChIP-seq), finding binding sites at genes influencing immunity and behavior. Finally, we investigated the immunological and enzymatic conditions affecting Vg cleavage and nuclear translocation, and constructed a 3D structural model. Our data are the first to show Vg in the nucleus and suggests a new fundamental regulatory role for this ubiquitous protein.

First record of Temnothorax convexus (Forel, 1894) in Portugal (Hymenoptera: Formicidae) with an updated checklist of ants from the country

The arboreal ant Temnothorax convexus (Forel, 1894) is reported for the first time in Portugal. A single colony was found nesting inside an abandoned gall near Lisbon. A full morphometric evaluation of the specimens is provided, including a small sample from the recently discovered population in South Iberia. High-definition photographs of the worker caste are given, together with a comparison with the most similar species in Iberia and an update of the Portuguese ant checklist.

Taxonomic revision of the Temnothorax salvini clade (Hymenoptera: Formicidae), with a key to the clades of New World Temnothorax

Temnothorax is a large myrmicine ant genus with a range spanning the northern hemisphere, including the northern half of the Neotropics. Many of the Neotropical species were originally placed in the now defunct genus Macromischa. Recent molecular work has revealed that distinct lineages of Neotropical Temnothorax have arrived by evolutionary convergenceat a morphological syndrome with characteristics that were used to diagnose the former genus Macromischa. One such lineage is the salvini clade, which in this study is redefined to contain 63 species, 35 of which are described as new. A key to all species of the salvini clade based on the worker caste is provided; additionally, a worker-based key to all clades of the New World is provided. The following species are redescribed: T. albispinus (Wheeler), T. androsanus (Wheeler), T. annexus (Baroni Urbani), T. augusti (Baroni Urbani), T. aztecus (Wheeler), T. ciferrii (Menozzi & Russo), T. flavidulus (Wheeler & Mann), T. fuscatus (Mann), T. goniops (Baroni Urbani), T. huehuetenangoi (Baroni Urbani), T. ixili (Baroni Urbani), T. leucacanthus (Baroni Urbani), T. nigricans (Baroni Urbani), T. ocarinae (Baroni Urbani), T. pastinifer (Emery), T. pergandei (Emery), T. politus (Smith), T. pulchellus (Emery), T. rugosus (Mackay), T. salvini (Forel), T. schwarzi (Mann), T. skwarrae (Wheeler), T. subditivus (Wheeler), T. tenuisculptus (Baroni Urbani), T. terricola (Mann), T. terrigena (Wheeler), T. torrei (Aguayo). The gynes of T. ciferrii, T. fuscatus, T. ixili, T. politus, T. rugosus, T. salvini, T. tenuisculptus and T. torrei are described. The males of T. albispinus and T. fuscatus are described. Lectotypes are designated for T. androsanus, T. annexus, T. augusti, T. aztecus, T. flavidulus, T. fuscatus, T. nigricans, T. pastinifer, T. pergandei, T. politus, T. pulchellus, T. salvini, T. skwarrae, T. subditivus, T. terricola, and T. terrigena. A neotype for Temnothorax salvini obscurior (Forel) is designated, the taxon is raised to species, and a replacement name is designated: T. longicaulis stat. nov., nom. nov. The following species are described as new: T. achii sp. nov., T. acuminatus sp. nov., T. acutispinosus sp. nov., T. agavicola sp. nov., T. altinodus sp. nov., T. arbustus sp. nov., T. aureus sp. nov., T. aztecoides sp. nov., T. bahoruco sp. nov., T. balaclava sp. nov., T. balnearius sp. nov., T. bison sp. nov., T. casanovai sp. nov., T. fortispinosus sp. nov., T. harlequina sp. nov., T. hippolytus sp. nov., T. laticrus sp. nov., T. leucacanthoides sp. nov., T. longinoi sp. nov., T. magnabulla sp. nov., T. misomoschus sp. nov., T. nebliselva sp. nov., T. obtusigaster sp. nov., T. paraztecus sp. nov., T. parralensis sp. nov., T. parvidentatus sp. nov., T. pilicornis sp. nov., T. quercicola sp. nov., T. quetzal sp. nov., T. rutabulafer sp. nov., T. terraztecus sp. nov., T. tuxtlanus sp. nov., T. wettereri sp. nov., T. wilsoni sp. nov., T. xincai sp. nov.

Description of two new species of ants of the genus Myrmecina Curtis, 1829 (Hymenoptera: Formicidae: Myrmicinae) from the Eastern Himalayas

Two new species of the ant genus Myrmecina Curtis, 1829, M. bawai sp. nov. and M. reticulata sp. nov., are described and illustrated based on the worker caste from Mizoram, Northeast India. The genus is reported for the first time from Mizoram, the Indian state with the highest percentage of forest cover. A key to the Indian fauna of Myrmecina is also provided based on the worker caste.

Queens of the inquiline social parasite Acromyrmex insinuator can join nest-founding queens of its host, the leaf-cutting ant Acromyrmex echinatior

Queens of the inquiline social parasite Acromyrmex insinuator are known to infiltrate mature colonies of Acromyrmex echinatior and to exploit the host’s perennial workforce by producing predominantly reproductive individuals while suppressing host reproduction. Here we report three cases of an A. insinuator queen having joined an incipient colony of A. echinatior that contained only the founding host-queen and her small symbiotic fungus garden. We conjectured that 1:1 host-inquiline co-founding—a phenomenon that has only rarely been reported in ants—may imply that the presence of an A. insinuator queen may incur benefits to the host by increasing survival of its incipient colonies. We observed that the parasite queens neither foraged nor defended the nest against intruders. However, the parasite queens interacted with the host and fungus in a way that could be consistent with grooming and/or with contributing eggs. These observations may help explain why A. insinuator queens have maintained metapleural glands, even though they are smaller than those of host queens, and why A. insinuator has lost the large foraging worker caste but not the small worker caste.