The Evolution of Flower Beetles as Visitors and Pollinators.

Shifting cultivation (jhum) is a major land use practice in Mizoram. It was considered as an eco-friendly and efficient method when the cycle duration was long (15-30years), but it poses the problem of land degradation and threat to ecology when shortened (4-5years) due to increased intensification of farming systems. Studying beetle community structure is very helpful in understanding how shifting cultivation affects the biodiversity features compared to natural forest system. The present study examines the beetle species diversity and estimates the effects of shifting cultivation practices on the beetle assemblages in relation to change in tree species composition and soil nutrients. Scarabaeidae and Carabidae were observed to be the dominant families in the land use systems studied. Shifting cultivation practice significantly (P < 0.05) affected the beetle and tree species diversity as well as the soil nutrients as shown by univariate (one-way analysis of variance (ANOVA), correlation and regression, diversity indices) and multivariate (cluster analysis, principal component analysis (PCA), detrended correspondence analysis (DCA), canonical variate analysis (CVA), permutational multivariate analysis of variance (PERMANOVA), permutational multivariate analysis of dispersion (PERMDISP)) statistical analyses. Besides changing the tree species composition and affecting the soil fertility, shifting cultivation provides less suitable habitat conditions for the beetle species. Bioindicator analysis categorized the beetle species into forest specialists, anthropogenic specialists (shifting cultivation habitat specialist), and habitat generalists. Molecular analysis of bioindicator beetle species was done using mitochondrial cytochrome oxidase subunit I (COI) marker to validate the beetle species and describe genetic variation among them in relation to heterogeneity, transition/transversion bias, codon usage bias, evolutionary distance, and substitution pattern. The present study revealed the fact that shifting cultivation practice significantly affects the beetle species in terms of biodiversity pattern as well as evolutionary features. Spatiotemporal assessment of soil-plant-beetle interactions in shifting cultivation system and their influence in land degradation and ecology will be helpful in making biodiversity conservation decisions in the near future.

Macaranga (Euphorbiaceae) is a large genus of dioecious trees with approx. 260 species. To date, only one pollination study of the genus has reported brood-site pollination by thrips in M. hullettii. In this study, the pollination system of Macaranga tanarius is reported. The study was conducted on Okinawa and Amami Islands, Japan. Flower visitors on M. tanarius were collected and their pollen load and behaviour on the flowers examined, as well as inflorescence structure and reward for the pollinators. The most abundant flower visitors found on the male and female inflorescences were Orius atratus (Anthocoridae, Hemiptera), followed by Decomioides schneirlai (Miridae, Hemiptera). Pollen load on O. atratus from flowering pistillate inflorescences was detected as well as from staminate flowers. Orius atratus and D. schneirlai are likely to use the enclosed chambers formed by floral bracts as breeding sites before and during flower anthesis, and feed on nectar on the adaxial surface of flower bracts. The extrafloral nectary has a ball-shaped structure and the contained nectar is not exposed; the hemipterans pierce the ball to suck out the nectar. The results indicate that the plant is pollinated by flower bugs breeding on the inflorescences. This study may be the first report of pollination systems in which flower bugs are the main pollinators. Similarity of pollination systems between M. hullettii and M. tanarius indicates that the two brood-site pollination systems have the same origin. The pollinator species belongs to a predacious group, whose major prey includes thrips. The pollination system might represent a unique example of evolution from predatory flower visitors feeding on the pollinators (thrips) to the main pollinators.

Floral variation among closely related species is thought to often reflect differences in pollination systems. Flowers of the large genus Impatiens are characterized by extensive variation in colour, shape and size and in anther and stigma positioning, but studies of their pollination ecology are scarce and most lack a comparative context. Consequently, the function of floral diversity in Impatiens remains enigmatic. This study documents floral variation and pollination of seven co-occurring Impatiens spp. in the Southeast Asian diversity hotspot. To assess whether floral trait variation reflects specialization for different pollination systems, we tested whether species depend on pollinators for reproduction, identified animals that visit flowers, determined whether these visitors play a role in pollination and quantified and compared key floral traits, including floral dimensions and nectar characteristics. Experimental exclusion of insects decreased fruit and seed set significantly for all species except I. muscicola, which also received almost no visits from animals. Most species received visits from several animals, including bees, birds, butterflies and hawkmoths, only a subset of which were effective pollinators. Impatiens psittacina, I. kerriae, I. racemosa and I. daraneenae were pollinated by bees, primarily Bombus haemorrhoidalis. Impatiens chiangdaoensis and I. santisukii had bimodal pollination systems which combined bee and lepidopteran pollination. Floral traits differed significantly among species with different pollination systems. Autogamous flowers were small and spurless, and did not produce nectar; bee-pollinated flowers had short spurs and large floral chambers with a wide entrance; and bimodally bee- and lepidopteran-pollinated species had long spurs and a small floral chamber with a narrow entrance. Nectar-producing species with different pollination systems did not differ in nectar volume and sugar concentration. Despite the high frequency of bee pollination in co-occurring species, individuals with a morphology suggestive of hybrid origin were rare. Variation in floral architecture, including various forms of corolla asymmetry, facilitates distinct, species-specific pollen-placement on visiting bees. Our results show that floral morphological diversity among Impatiens spp. is associated with both differences in functional pollinator groups and divergent use of the same pollinator. Non-homologous mechanisms of floral asymmetry are consistent with repeated independent evolution, suggesting that competitive interactions among species with the same pollination system have been an important driver of floral variation among Impatiens spp.

One view of pollination systems is that they tend toward specialization. This view is implicit in many discussions of angiosperm evolution and plant—pollinator coevolution and in the long—standing concept of pollination syndromes. But actual pollination systems often are more generalized and dynamic than these traditions might suggest. To illustrate the range of specialization and generalization in pollinators' use of plants and vice versa, we draw on studies of two floras in the United States, and of members of several plant families and solitary bee genera. We also summarize a recent study of one local flora which suggests that, although the colors of flowers are aggregated in phenotype space, there is no strong association with pollinator types as pollination syndromes would predict. That moderate to substantial generalization often occurs is not surprising on theoretical grounds. Plant generalization is predicted by a simple model as long as temporal and spatial variance in pollinator quality is appreciable, different pollinator species do not fluctuate in unison, and they are similar in their pollination effectiveness. Pollinator generalization is predicted when floral rewards are similar across plant species, travel is costly, constraints of behavior and morphology are minor, and/or pollinator lifespan is long relative to flowering of individual plant species. Recognizing that pollination systems often are generalized has important implications. In ecological predictions of plant reproductive success and population dynamics it is useful to widen the focus beyond flower visitors within the correct" pollination syndrome, and to recognize temporal and spatial fluidity of interactions. Behavioral studies of pollinator foraging choices and information—processing abilities will benefit from understanding the selective advantages of generalization. In studies of floral adaptation, microevolution, and plant speciation one should recognize that selection and gene flow vary in time and space and that the contribution of pollinators to reproductive isolation of plant species may be overstated. In conservation biology, generalized pollination systems imply resilience to linked extinctions, but also the possibility for introduced generalists to displace natives with a net loss of diversity.

Pollination in New Zealand, an isolated oceanic archipelago in the Southern Hemisphere, has previously been characterised as having low rates of self‐incompatibility and a lack of specialised pollination, as well as little pollinator dependence. These features have been interpreted as supportive of “Baker's Rule”, which suggests that long‐distance colonisation selects for breeding systems that do not require biparental mating. However, we show that recent studies of the angiosperm flora reveal sexual systems (sexual dimorphism, self‐incompatibility, monoecy, dichogamy, and herkogamy) that usually involve a dependence on pollen vectors. The level of self‐incompatibility in the flora, though still poorly known, should be regarded as moderate rather than unusually low (about 36% of hermaphrodite populations tested are strongly or partially self‐incompatible), though many more species remain to be tested. As found elsewhere, incompatibility is higher in the trees and shrubs (around 80%) compared with herbs (21%). Moreover, high rates of autonomous selfing have been demonstrated empirically in only 21% of the self‐compatible species, demonstrating that they are not regular selfers. The pollinator dependence that these features impose makes much of the flora vulnerable to declines in pollinator service. Pollination systems in New Zealand have been characterised as unspecialised, imprecise entomophilous systems that correspond to the predominance of small white or pale flowers with dish or bowl shapes. We use a two‐tiered conceptual framework incorporating a coarse‐scale blossom class analysis and a finer scale syndrome concept analysis to assess the level of specialisation in plant‐pollinator relationships of New Zealand. Within each of the syndromes is a continuum of blossom classes: open‐, directed‐, and closed‐access. Highly specialised systems are found in closed‐access blossoms but they are not common in New Zealand (e.g., Solanum, Carmichaelia, orchids, and mistletoes). Large directed‐access blossoms are primarily associated with bird pollination but certain small entomophilous blossoms, called “knob” blossoms (Pseudopanax, Geniostoma), are also important for perching birds and may be considered ornithophilous. Bats and lizards play a minor role in pollination. Moth pollination is not well studied and may reveal cryptic specialisation based on scent. The majority of pollination systems in New Zealand correspond to the “small bee syndrome”, which is a generalised bee‐pollinated system common elsewhere and includes visits from flies and other diverse insects. Naturalised exotic bees may have both positive and negative effects on indigenous pollination systems and could play a significant role in invasive mutualisms in which some weeds are specialised to their services. Future research in New Zealand pollination and breeding systems needs to focus on endangered mutualisms, particularly in birds; on invasive mutualisms, particularly for offshore islands; and on community analyses that evaluate exotic‐indigenous interactions and the potential for specialisation in the poorly known insect pollination systems.

The amount and genetic composition of pollen grains that are transported to flowers influence the reproduction and fitness of plants. Despite the importance of insect-pollination systems, an understanding of those systems is still lacking due to the absence of a genetic analysis of pollen grains that are transported to flowers. We evaluated the pollination efficiencies of bumblebees (Apidae, Bombus spp.), flower beetles (Scarabaeidae, subfamily Cetoniinae, Protaetia and Eucetonia sp.), and small beetles (Lagriidae, Arthromacra sp.) that visited the flowers of Magnolia obovata (Magnoliaceae) using quantitative (flower visitation frequency, amount of adherent pollen per insect) and qualitative (origin and genetic diversity of adherent pollen per insect) criteria. Most of the pollen adhering to bumblebees and small beetles was self-pollen. This result suggests that visitation by these insects may cause geitonogamous pollen flow and negatively affect the reproduction of M. obovata, causing inbreeding depression. In contrast, flower beetles transported large amounts of genetically diverse outcross pollen. Our results suggest that certain beetle species contribute quantitatively and qualitatively to the pollination of M. obovata. Direct genetic analysis of pollen grains will advance our understanding of plant mating systems and may shed light on the mutualism and coevolution of plants and flower visitors.

Insects are well recognised as being the major contributor to global biodiversity, and for their critical involvement in many biotic interactions. Most of the insect diversity is found in tropical rainforests. However, these forests are threatened by high rates of clearing and the subsequent fragmentation of remaining habitat. The effects on biota, particularly insects, are poorly understood as are the mechanisms mediating faunal changes. Reforestation could potentially alleviate some of the deleterious effects of forest loss and fragmentation. However, because reforestation is a relatively new endeavour, it is little known just how much insect biodiversity can be supported by reforestation and what factors influence insect colonisation. These issues were investigated in the Atherton Tablelands of north-eastern Australia, a landscape whose rainforest has been heavily cleared and fragmented over the last 80 years, but is also the focus of reforestation efforts. To quantify the effects of rainforest loss and fragmentation, pasture sites were compared with small rainforest fragments, and with the edges and interiors of large rainforest fragments (24 sites in total). Sites with replanted rainforest (planted with a high diversity of plants) were also included. These varied in their age (2-17 yrs) and their distance (0-4.5 km) from existing rainforest (24 sites in total). Another set of reforested sites was also studied but these differed in their planting style (number of plant species, spacing etc). This second set of sites was located in two regions: the Atherton Tablelands (50 sites), and in the subtropics of eastern Australia (54 sites). At each site, beetle assemblages were surveyed using methods that sample beetles near the ground (four ground-based flight interception traps in the first set of sites and ten pitfall traps in the second set of sites), and then the assemblages among site-types were compared. Over 32,000 beetles were caught and identified to the level of family, and of these, 15,206 were identified further to the level of species. Very few beetle species were present in pasture, suggesting that converting rainforest into pasture has a very strong negative effect on beetle diversity and species composition. Irrespective of rainforest fragment size, beetle species composition in drier rainforest habitats was different from that of moister rainforest. Beetle species composition also differed between small remnants and interior rainforest: drier-associated species were more abundant in small remnants, whereas wetter-associated species were more abundant in interiors. This pattern can be best attributed to a fragmentation effect mediated by differences in microclimate. With the exception of differences between rainforest and pasture, these results were generally not observed among beetle assemblages identified to coarser taxonomic groups (family, feeding guild, and body size). Among replanted rainforest, older sites and those adjacent to rainforest had a more rainforest-like beetle species composition. However, even the closer and older sites had a substantially lower abundance and richness of rainforest-associated beetles than did rainforest. Age effects were generally stronger than distance effects. Beetle assemblage similarity to rainforest was more strongly correlated with structural similarity to rainforest than with site age or distance from rainforest. Thus the use of revegetation techniques which lead to more rainforest-like structural conditions appears to be of over-riding importance in catalysing the rapid acquisition of rainforest beetle assemblages in the initial stages of restoration. Nevertheless, not all beetle species were equally affected by the factors tested. Large-bodied beetle species (&gt;5 mm) were more strongly influenced by distance than small-bodied species (&lt;5 mm), suggesting that small-bodied species are better dispersers, and thus are amongst the first to colonise new habitats. Spatial ubiquity in rainforest was not a good predictor of a species' dispersal ability. Interestingly, fewer of the broader groups (family, feeding guild, and body size) showed the response to distance evident at the species level although they showed differences between reforested sites differing in age, and between reforested and reference site-types. Therefore, these results and those from the fragmentation study suggest that information at the species level is more sensitive to environmental change than data identified to a coarser level of taxonomy or grouped according to feeding ecology or body size. For the pitfall-trapped beetles in the second reforested site network, beetle assemblages in all styles of reforestation were intermediate in species composition between pasture and rainforest. The similarity of beetle assemblages to intact rainforest increased with the age and structural complexity of reforested sites, although again structural complexity appeared to be of overriding importance. This study has shown that even small patches of rainforest and reforested areas can support diverse rainforest-dependent beetle assemblages. A range of factors influence the development of beetle assemblages in reforested sites although not all species are equally affected. However, even structurally complex reforested sites cannot provide a short- or medium-term substitute for the retention of intact rainforest.

Summary Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co‐evolve. World‐wide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed‐effects models, we tested whether flower visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower visitor species diversity and abundance. Flower visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower visitor species diversity. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower visitor abundance, species richness and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar. Synthesis and applications. Despite contrasting floral traits for crops world‐wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species.

Forest canopies provide important resources for insect communities via flowers. Yet, pollination systems of tall forest trees are poorly studied, resulting from the difficulties in observing pollinator activity at the canopy level and great temporal variation in flower production. In temperate forest canopies of the southern hemisphere, small, whitish and generalist flowers seem to dominate. Here, we observed insect flower visitors, at the canopy level, to four southern Afrotemperate forest tree species bearing small, white to green flowers in a large, indigenous forest. Additionally, we quantified flower traits and collected pollen from representative insect visitors. A total of 105 insect species, from 48 families and 7 orders, were observed visiting flowers. In terms of total flower visits, the generalist Cape honey bee (Apis mellifera capensis) made up ca. 57% of all flower visits. A third of the total observation time covered crepuscular to nocturnal flower visits; yet only 12.68% of total visits took place during this time. Interestingly, despite both trees and insects being largely generalist in their interactions with one another (supported by the presence of conspecific and heterospecific pollen on most flower visitors), some insect species showed strong preferences for specific species of tree, driving dissimilar, interspecific assemblages of flower visitors. The pollinator community disparity may be explained through the unique and dissimilar floral traits for each tree species, both in flower size and in petal reflectance. We conclude that within generalist pollination systems, distinct and non‐random mutualisms can develop between different species of plants and a diverse suite of pollinators, and that floral traits could partially predict such interactions.

The interactions between flowers and the insects that pollinate them have fascinated scientists for more than 200 years. The last century saw the establishment of the fundamental concept of pollination syndromes which allows classification of flowers according to the agents that pollinate them demonstrating specialisation and co-evolution of plants and pollinators. This concept has recently been questioned and the contrary, ubiquitous generalisation and chance have been proposed to be the driving forces behind plant – pollinator interactions on an individual and community level. The present study was carried out to address the question of the level of pollinator dependence and generalisation in pollination systems in an alpine plant community in alpine New Zealand. Initial research in New Zealand alpine habitats had lead to the assumption of minor importance of insect pollination as the alpine flora in New Zealand in general is not very conspicuous and the available potential insect pollinators are mainly flies and short-tongued native bees. Therefore it had been proposed that the level of autogamy and generalisation in pollination interactions in a high-alpine habitat should be high. However, it could be demonstrated that the majority of the 23 plant species in the alpine community depend on pollinator service to achieve reproductive success. A total of 87% of plant species under investigation are at least in part self-incompatible and therefore rely on pollinator service for outcross-pollen delivery. Moreover, it could be shown that the pollinators that transfer pollen do not choose plants at random. The pollination systems in the alpine community proved to consist of both rather specialised and rather generalised functional pollinator groups, moths and native bees belonging to the former and syrphid flies belonging to the latter. Furthermore, there was strong evidence that flower visitors do not automatically equal pollinators and that pollination efficiency differed between functional groups. When assessing the floral cues, e.g. flower colour and scent that attract a certain functional pollinator group, no clustering of the attractants in correlation with pollinator group could be demonstrated. However, the individual combination of colour and scent rendered each plant species distinct from most others. This novel feature of the alpine plant community may be interpreted as a way to facilitate associative pollinator learning. A foraging pollinator can easily memorise distinct flowers and subsequently proceed to direct visitation to repeat the experience of rewards. This way flower constancy and increased efficiency of pollen transfer is promoted allowing plants to benefit from adequate pollen delivery and xenogamous reproduction resulting in genetically diverse progeny that has a greater potential of survival in the challenging alpine environment.

Differences in the diversity and composition of the pollinator assemblage of two co-flowering congeneric alpine wallflowers, Erysimum nevadense and E. baeticum

Nectar production in flowers has been associated with pollination systems and seen as part of plant reproductive strategies. But other factors may have a role on nectar features and its efficacy as reward. We investigated pollination system of Qualea grandiflora, the most widespread woody species of Cerrado, the Neotropical savannas in Central Brazil, focusing on nectar features, their relationship with nocturnal and diurnal pollinators and how nectar affects male fitness, measured through pollen removal. Qualea grandiflora flowers during rainy season; anthesis starts at dusk, with a slightly sweet scent, pollen release and receptive stigma. Flowers remained opened until next evening and were visited and pollinated by a wide range of nocturnal and diurnal animals. Hawk moths were more frequent and responsible for most Q. grandiflora male fitness. Nectar was secreted during the night and early morning, with maximum accumulated volume up to 20.9 μl. Sugar concentration (23.12%) and amount (1.79 mg) remained constant during flower lifespan. No signals of active nectar resorption were observed. Nectar sugar composition was sucrose dominant during the night, and sucrose and hexose rich during the day. Standing crop measurements indicated an important proportion of nectar intake by flower visitors. Qualea grandiflora seemed to synchronize its floral and nectar features with hawk moths. However, nectar composition encompasses general preferences by both diurnal and nocturnal pollinators, assuring a mixed pollination system which seems well adapted to the species continental-scale distribution.

Faunal composition of scarabaeids associated with rose cultivation in Bangalore districts of Karnataka (India) was investigated. During the field survey, thirteen species of scarabaeid beetles belonging to nine genera representing three sub families: Melolonthinae, Rutelinae, and Cetoniinae were recorded. Maximum of five species belong to subfamily Melolonthinae and each three species belong to Rutelinae, and Cetoniinae. Among the identified species, Holotrichia seerata, Schizonycha ruficollis, Anomala bengalensis , and Adoretus versutus were found to be the most dominant leaf feeders and Maladera sp. and Apogonia ferruginea was found to be infesting more on flowers on rose. The scarabaeids adults' emergence began after the 1 st rain in April and it was continued up to the last week of September in Bangalore condition. Maximum numbers of adults were recorded between 19.00 and 19.30 hrs and thereafter no emergence/ a little emergence was noticed from each species of scarabaeids. The degree of leaf damage caused by H. seerata, S. ruficollis , and A. versutus were significantly more on rose leaf irrespective of presence or absence of flowers. The outcome of the study may be helpful in pest management especially of rose plantation.

Ants Like Flower Nectar

Aerial traps composed of plastic water bottles baited with attractive liquids are often used to inventory beetles, especially longhorns (Cerambycidae) and flower beetles (Scarabaeidae: Cetoniinae). Many different bait mixtures exist but their effectiveness has rarely been scientifically tested. Six different mixtures, involving red wine, white wine, lager beer, apple juice, and vinegar, as well as a water and sugar control, were compared. Fourteen replicates of the seven attractants were arranged in a thermophilic oak forest in the southwest of France. In terms of abundance and richness per trap, two attractants proved to be significantly less effective: The control and the juice mixture. The other five are equivalent for richness. For flower beetles, red wine + white wine and beer + sugar mixtures collected significantly more individuals. However, the sample collected by the beer + sugar mixture showed a lower diversity than the other wine + beer mixtures, due to the dominance of a few species of flower beetles. In terms of species composition, there was no qualitative difference between the attractants. Taking abundance into account (Bray-Curtis index), the beer + sugar blend differed from the others due to the high abundance of Cetonia aurata (Linnaeus, 1758). This study provides reasonable confidence that inventories conducted with different baits based on red wine or beer return comparable results. Finally, we recommend the beer + red wine mixture, which presents a good compromise between abundance and diversity for the different families, and is already frequently used.