Cockroaches as pollinators of Clusia aff. sellowiana (Clusiaceae) on inselbergs in French Guiana

Cockroach pollination ensures sexual reproduction in the non-photosynthetic plant Balanophora tobiracola

While Coleoptera, Diptera, Hymenoptera, and Lepidoptera have traditionally been recognized as key pollinators, recent studies suggest that other insect groups, such as Blattodea (cockroaches), may also play a significant role. However, direct evidence of fruit set resulting from cockroach pollination remains limited, even in plants presumed to rely on this mode of pollination. This study investigated the breeding system of the non-photosynthetic plant Balanophora tobiracola on Yakushima Island, Japan, with a particular focus on the potential occurrence of agamospermy. Additionally, the research rigorously evaluates the pollination effectiveness of cockroaches and ants in B. tobiracola by assessing reproductive success exclusively through their visits. Pollination experiments revealed high fruit set even under emasculation, indicating that agamospermy ensures seed production. However, B. tobiracola still relies heavily on pollinator activity for sexual reproduction. Ants and cockroaches were identified as effective pollinators, whereas contributions of pyralid moths, crane flies, and nitidulid beetles-whose larvae consume B. tobiracola infructescences-were negligible. Notably, a single visit from certain cockroach species significantly enhanced pollination. The above findings demonstrate that B. tobiracola is effectively pollinated by cockroaches and ants. Combining unusual pollinators with agamospermy likely facilitates the reproductive success of B. tobiracola in dense forest understories where typical pollinators, like bees, are scarce. Our results underscore the need to reassess the role of agamospermy as reproductive assurance and the significance of cockroaches and ants as pollinators, particularly for plants in shaded understory habitats.

Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus

BACKGROUND AND AIMS

Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model.

METHODS

The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus.

KEY RESULTS

The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission.

CONCLUSIONS

Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.

Specialized cockroach pollination in the rare and endangered plant Vincetoxicum hainanense in China

PREMISE

Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were designed to provide direct proof of cockroach pollination and compare the effectiveness of other flower visitors.

METHODS

We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition, we reviewed reports of cockroaches as pollinators of other plants and analyzed the known pollination systems in Vincetoxicum in a phylogenetic context.

RESULTS

The small, pale green flowers of V. hainanense opened during the night. The flowers were not autogamous, but were self-compatible. Flower visitors included beetles, flies, ants and bush crickets, but the most effective pollinator was the cockroach Blattella bisignata, the only visitor that carried pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Plants in this genus are predominantly pollinated by flies, moths and wasps.

CONCLUSIONS

Globally, only 11 plant species are known to be cockroach-pollinated. Because their range of floral features encompass similarities and differences, defining a "cockroach pollination syndrome" is difficult. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.

Pollination efficiency of cockroaches and other floral visitors of Clusia blattophila

Cockroaches have rarely been documented as pollinators. In this paper we examine whether this is because they might be inefficient at pollination compared to other pollinators. Clusia blattophila, a dioecious shrub growing on isolated rocky outcrops in French Guiana, is pollinated by Amazonina platystylata cockroaches and provides a valuable system for the study of cockroach pollination efficiency. We examined the species composition of the visitor guild and visitation rates by means of camcorder recordings and visitor sampling. Then, we investigated the capacity for pollen transfer of principal visitors and found correlations between visitation rates and pollen loads on stigmas. In an exclusion experiment we determined the contributions of individual species to pollination success. Amazonina platystylata, crickets and two species of Diptera transferred pollen, but the number of transferred pollen grains was only related to visitation rates in the case of cockroaches. Crickets visited and rarely carried pollen. Dipterans were as frequent as cockroaches, carried similar pollen loads, but transferred much less pollen. An estimated 41% and 17% of ovules were pollinated by cockroaches and dipterans, respectively. The remaining ovules were not pollinated. There was no spatial variation in pollinator guild composition, but cockroaches visited flowers less frequently at the smaller study site. We demonstrate that cockroaches pollinate a large proportion of ovules. Their pollination service is not confined to one study site and, unlike that provided by dipterans, is not limited to certain years. We suggest that cockroach pollination has been overlooked and that cockroach-pollinated plants, which share certain floral features, possess adaptations to pollination by cockroaches.

Social wasps, crickets and cockroaches contribute to pollination of the holoparasitic plant Mitrastemon yamamotoi (Mitrastemonaceae) in southern Japan

Mitrastemon yamamotoi is completely embedded within the tissues of its hosts, except during the reproductive stage, when aboveground parts emerge from host tissues. Its highly modified appearance has attracted attention of many botanists, but very little is known about the reproductive system. Floral visitors to M. yamamotoi were observed in southern Japan. Pollination experiments were conducted to determine the plant's self-compatibility and pollen limitation, as well as the contribution of diurnal and nocturnal visitors to fruit set and outcrossing. Mitrastemon yamamotoi is mainly pollinated by social wasps, but previously unnoticed pollinators (i.e. crickets and cockroaches) are also important, based on visitation frequency and pollen loads. Results of the pollination experiments suggest that nocturnal visitors, such as crickets and cockroaches, contribute to geitonogamous pollination, whereas diurnal visitors, such as social wasps, facilitate outcrossing. The unexpected pollinator assemblage of M. yamamotoi might be influenced by multiple factors, including the highly modified flowers that are produced close to the ground in dark understorey environments, the species' winter-flowering habit and the location of the study site (i.e. near the northern limit of the species' range). Considering that M. yamamotoi occurs widely in subtropical and tropical forests in Asia, additional studies are needed to assess pollinator assemblages of M. yamamotoi at other locations.

Identification of attractive blend for spotted wing drosophila, Drosophila suzukii, from apple juice

Drosophila suzukii, commonly known as the spotted wing drosophila (SWD), is an exotic fruit fly from Southeast Asia that was introduced to the temperate regions of North America and Europe in 2008. It attacks a wide variety of fruits and has become a devastating pest of soft-skinned fruit crops. Due to the rapid spread of SWD across the newly invaded continents, fresh fruit markets have a zero-tolerance policy regarding D. suzukii infestation. Specific and efficient D. suzukii detection tools are urgently needed so that farmers can deliver timely management interventions to meet market demands. Since SWD is known to be attracted to damaged and rotting fruits, headspace volatiles from fresh and fermented apple juices were collected and analyzed by gas chromatography-mass spectrometry. Special attention was given to the compounds produced and/or enriched during the fermentation process. After performing a series of laboataory and field tests, we identified a quinary blend, which is more efficient and selective for D. suzukii than the currently standard apple cider vinegar and commercially available SWD lure under field conditions. Identification of SWD attractant will help growers accurately detect D. suzukii adult infestations in orchards, thereby allowing for timely pest management interventions while reducing conventional insecticidal usage to protect our crops, environment, and ecosystem.

Pollination of Campomanesia phaea (Myrtaceae) by night-active bees: a new nocturnal pollination system mediated by floral scent

Bees are the most important diurnal pollinators of angiosperms. In several groups of bees a nocturnal/crepuscular habit developed, yet little is known about their role in pollination and whether some plants are adapted specifically to these bees. We used a multidisciplinary approach to investigate the reproductive biology and to understand the role of nocturnal/crepuscular bees in pollination of Campomanesia phaea (Myrtaceae), popularly named cambuci. We studied the floral biology and breeding system of C. phaea. We collected the floral visitors and tested the pollinators' effectiveness. We also determined the floral scents released at night and during daytime, and studied behavioural responses of crepuscular/nocturnal bees towards these scents. The flowers of cambuci were self-incompatible and had pollen as the only resource for flower visitors. Anthesis lasted around 14 h, beginning at 04:30 h at night. The flowers released 14 volatile compounds, mainly aliphatic and aromatic compounds. We collected 52 species of floral visitors, mainly bees. Nocturnal and crepuscular bees (four species) were among the most frequent species and the only effective pollinators. In field bioassays performed at night, nocturnal/crepuscular bees were attracted by a synthetic scent blend consisting of the six most abundant compounds. This study describes the first scent-mediated pollination system between a plant and its nocturnal bee pollinators. Further, C. phaea has several floral traits that do not allow classification into other nocturnal pollination syndromes (e.g. pollinator attraction already before sunrise, with pollen as the only reward), instead it is a plant specifically adapted to nocturnal bees.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Clusiaceae

Resumo Apresentamos o tratamento de Clusiaceae para a flora das cangas da Serra dos Carajás, Pará, Brasil. São reconhecidas três espécies de Clusia: C. nemorosa, C. panapanari e C. aff. weddelliana, além de Garcinia madruno e Symphonia globulifera. Clusia aff. weddelliana apresenta algumas diferenças marcantes com os demais espécimes provenientes de outras localidades do Pará. São apresentadas descrições, ilustrações e comentários taxonômicos sobre as espécies.

Listagem da entomofauna antófila do estado de Mato Grosso do Sul, Brasil

RESUMO Apresentamos listagem da entomofauna visitante de flores do estado de Mato Grosso do Sul (MS) com base na compilação de informações obtidas em 17 estudos, a maioria realizado em áreas de Cerrado (n = 11) e menos frequentemente no Pantanal (n = 6). Foram registrados 10 grupos de insetos, pertencentes a seis ordens, 80 famílias e 411 espécies. Maior riqueza foi amostrada para o Cerrado (307 spp.) que Pantanal (147 spp.), com somente 43 espécies (10,4%) em comum entre estes biomas. Anthophila foi o grupo mais rico (155 spp.), seguido por besouros (82), borboletas/mariposas (53) e vespas (45), que junto totalizaram 81,5% das espécies. Maior riqueza de abelhas está relacionada ao fato da maioria dos trabalhos enfocarem este grupo, além da especialização deste grupo na utilização de recursos florais. Surpreendente foi o segundo lugar ocupado por besouros em relação a outros visitantes mais “ativos” e “habituais”, como lepidópteros e moscas. Em MS os acervos e grupos de pesquisa com entomofauna antófila são restritos e/ou incipientes, sendo necessário fortalecimento dos mesmos através de parcerias, intercâmbios e formação de recursos humanos na área.

Physiology of environmental adaptations and resource acquisition in cockroaches

Cockroaches are a group of insects that evolved early in geological time. Because of their antiquity, they for the most part display generalized behavior and physiology and accordingly have frequently been used as model insects to examine physiological and biochemical mechanisms involved with water balance, nutrition, reproduction, genetics, and insecticide resistance. As a result, a considerable amount of information on these topics is available. However, there is much more to be learned by employing new protocols, microchemical analytical techniques, and molecular biology tools to explore many unanswered questions.

Density dependence in flower visitation rates of cockroach-pollinated Clusia blattophila on the Nouragues inselberg, French Guiana

The effective floral neighbourhood is the radius around a plant where the density of flowering plants and other factors affect visitation rates and pollination success of plants. This study aims to determine this radius and focuses on the effects of conspecific plant density, plant sex and the amount of shrub vegetation on visitation rates of Clusia blattophila, a dioecious bush pollinated by Amazonina platystylata cockroaches. The number of visits did not differ between flower sexes but cockroaches spent less time on the rewardless female flowers. The density effect was scale dependent. The distribution of flowering individuals within the 15-m radius had a significant positive effect on flower visitation rates. At a larger scale (35–45-m radius), an increase in density of male plants led to a decrease in visitation rates, indicating competition for pollinators. Within the smaller radius, the facilitative effect was probably induced by elevated floral advertisement and high mobility of cockroaches at this scale. Within the larger radii, the results indicated that cockroach mobility was restricted and population density was stable at this scale. Density of male plants affected visitation rates because only male plants reward pollinators. Hence, male plants were the true competitors.

Phytochemicals to suppress Fusarium head blight in wheat-chickpea rotation

Fusarium diseases cause major economic losses in wheat-based crop rotations. Volatile organic compounds (VOC) in wheat and rotation crops, such as chickpea, may negatively impact pathogenic Fusarium. Using the headspace GC-MS method, 16 VOC were found in greenhouse-grown wheat leaves: dimethylamine, 2-methyl-1-propanol, octanoic acid-ethyl ester, acetic acid, 2-ethyl-1-hexanol, nonanoic acid-ethyl ester, nonanol, N-ethyl-benzenamine, naphthalene, butylated hydroxytoluene, dimethoxy methane, phenol, 3-methyl-phenol, 3,4-dimethoxy-phenol, 2,4-bis (1,1-dimethyethyl)-phenol, and 1,4,7,10,13,16-hexaoxacyclooctadecane; and 10 VOC in field-grown chickpea leaves: ethanol, 1-penten-3-ol, 1-hexanol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, trans-2-hexenal, 3-methyl-1-butanol, 3-hydroxy-2-butanone, 3-methyl-benzaldehyde and naphthalene. Also found was 1-penten-3-ol in chickpea roots and in the root nodules of two of the three cultivars tested. Chickpea VOC production pattern was related (P=0.023) to Ascochyta blight severity, suggesting that 1-penten-3-ol and cis-3-hexen-1-ol were induced by Ascochyta rabiei. Bioassays conducted in Petri plates established that chickpea-produced VOC used in isolation were generally more potent against Fusarium graminearum and Fusarium avenaceum than wheat-produced VOC, except for 2-ethyl-1-hexanol, which was rare in wheat and toxic to both Fusarium and tetraploid wheat. Whereas exposure to 1-penten-3-ol and 2-methyl-1-propanol could suppress radial growth by over 50% and octanoic acid-ethyl ester, nonanol, and nonanoic acid-ethyl ester had only weak effects, F. graminearum and F. avenaceum growth was completely inhibited by exposure to trans-2-hexenal, trans-2-hexen-1-ol, cis-3-hexen-1-ol, and 1-hexanol. Among these VOC, trans-2-hexenal and 1-hexanol protected wheat seedlings against F. avenaceum and F. graminearum, respectively, in a controlled condition experiment. Genetic variation in the production of 2-ethyl-1-hexanol, a potent VOC produced in low amount by wheat, suggests the possibility of selecting Fusarium resistance in wheat on the basis of leaf VOC concentration. Results also suggests that the level of Fusarium inoculum in chickpea-wheat rotation systems may be reduced by growing chickpea genotypes with high root and shoot levels of trans-2-hexen-1-ol and 1-hexanol.

Aspects of reproductive ecology of Clusia valerioi Standl. and Clusia peninsulae Hammel (sp. nov.), two Central American species of Clusiaceae with resin flowers

Clusia valerioi Standl. and C. peninsulae Hammel, sp. nov. (formally established in the Appendix), two Central American species of Clusiaceae offering resin as a floral reward, were studied in the Piedras Blancas National Park, SW Costa Rica. Basic data on phenology, flower structure, course of anthesis, flower visitors, flower visitation and pollination processes, fruit development and seed dispersal are communicated. Resin collection and pollen release are reported and documented in greater detail. The significance of stingless bees for pollination is confirmed, but honeybees were also observed to visit the flowers and to collect resin. The seeds of C. valerioi, exhibiting a clearly ornithochorous character syndrome, were observed to be eaten and dispersed by four species of the tanager family (Thraupidae) and one species of finch (Fringillidae). Ants were also observed to carry away the seeds.