Functional homogenization of flower visitor communities with urbanization

Land‐use intensification and resulting habitat loss are put forward as the main causes of flower visitor decline. However, the impact of urbanization, the prime driver of land‐use intensification in Europe, is poorly studied. In particular, our understanding of whether and how it affects the composition and functioning of flower visitor assemblages is scant, yet required to cope with increasing urbanization worldwide. Here, we use a nation‐wide dataset of plant‐flower visitor (Coleoptera, Diptera, Hymenoptera, Lepidoptera) interactions sampled by citizen scientists following a standardized protocol to assess macroecological changes in richness and composition of flower visitor communities with urbanization. We measured the community composition by quantifying the relative occurrence of generalist and specialist flower visitors based on their specialisation on flowering plant families. We show that urbanization is associated with reduced flower visitor richness and a shift in community composition toward generalist insects, indicating a modification of the functional composition of communities. These results suggest that urbanization affects not only the richness of flower visitor assemblages but may also cause their large‐scale functional homogenization. Future research should focus on designing measures to reconcile urban development with flower visitor conservation.     

Communication interference in sympatrically occurring moth species

In moth species, females emit a species‐specific sex pheromone that is perceived over long distance by conspecific males. The species‐specificity in the chemical communication channel is achieved by a combination of unique components in specific ratios and sometimes also by interspecific behavioural antagonists to deter sympatrically occurring heterospecific males. In this study, we determined possible antagonistic effects in Helicoverpa gelotopoeon Dyar (Lepidoptera: Noctuidae) males to the major sex pheromone component of sympatrically occurring heliothine moths, Z11‐16:Ald, as well as to the sex pheromone of the sympatrically occurring Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) (Z11‐16:Ald and Z9‐14:Ald). We also explored whether other co‐occurring species are attracted to these pheromone blends. Our field experiments showed that the addition of Z11‐16:Ald alone or in combination with Z9‐14:Ald inhibited trap catches of H. gelotopoeon males and that this inhibition depended on the concentration of these compounds. In addition, other moth species were attracted to the blends. Together, our results confirm the antagonistic effect of heterospecific sex pheromone compounds of H. virescens to H. gelotopoeon.     

Sensitive and selective turn‐on fluorescence method for cetyltrimethylammonium bromide determination based on acridine orange–polystyrene sulfonate complex

This work proposed a rapid and novel fluorescence‐sensing system using a complex of acridine orange (AO) and polystyrene sulfonate (PSS) to sensitively recognize and monitor cetyltrimethylammonium bromide (CTAB) in an aqueous medium. AO can interact with PSS and a complex is formed via electrostatic attraction and hydrophobic interaction. The fluorescence of AO is greatly quenched after the introduction of PSS. Upon its subsequent addition, CTAB can interact and form a complex with PSS because the electrostatic attraction between CTAB and PSS is much stronger than that between AO and PSS, which results in significant fluorescence recovery. Interestingly, the proposed method can be applied for the discrimination and detection of surfactants with different hydrocarbon chain lengths due to their different binding affinity toward PSS. The detection limit for CTAB is as low as 0.2 µg/mL and the linear range is from 0.5 to 3.5 µg/mL. Moreover, we applied the sensor to the successful detection of CTAB in water samples. Copyright © 2015 John Wiley & Sons, Ltd.     

寄主植物挥发物对梨小食心虫受孕雌虫的引诱作用初探

梨小食心虫Grapholita molesta(Busck),是一种世界性的蛀果害虫。利用产卵选择试验研究了15种寄主植物挥发物对梨小食心虫受孕雌虫的产卵引诱活性。室内试验表明:受孕雌虫对不同挥发物的产卵选择趋性不同,其中对叶醇和己酸丁酯表现出明显的产卵选择趋性。为验证寄主挥发物对受孕雌虫的实际诱捕效果,进行了田间诱捕试验。结果发现,挥发物中己酸丁酯、苯甲腈、叶醇、E-2-己烯醛以及乙酸己酯诱捕到的雌虫均为受孕雌虫,显著高于空白对照及其他物质,其中己酸丁酯的平均诱捕量最多,苯甲腈次之,E-2-己烯醛、乙酸己酯这两种物质的平均诱捕量分别为第三、第四,叶醇的诱捕量低于乙酸己酯,其余物质的诱捕量均较低。综合室内及田间试验结果发现,寄主植物挥发物对受孕雌虫的引诱作用也随它们之间的作用距离表现出一定的差异性。     

Methods for studying cultural attraction

Cultural attraction theory (CAT) describes a general evolutionary process, cultural attraction, by which the spread and stability of cultural items (beliefs, practices, artifacts, etc.) result not just from differential reproduction, but also from transformations that systematically favor the reconstruction of cultural items of specific types. In this way, CAT aims to provide a general framework for the study of cultural evolution. In a thoughtful critical analysis, Buskell questions the ability of CAT to provide methodological guidance for research in cultural evolution. Can CAT be used to develop the sort of mid‐range theories and models that often drive empirical work? Here we argue that CAT can indeed be used in this way, and we outline the methodological practices that students of cultural attraction have used and are currently developing.     

EAG and behavioral responses of the wingless tea aphid Toxoptera aurantii (Homoptera: Aphididae) to tea plant volatiles

Electrophysiological and behavioral responses of the wingless tea aphid, Toxoptera aurantii (Boyer), to 14 synthetic volatiles identified from tea shoots, their partial (GLV mixture) and full (ACB mixture) blends, and fresh young tea leaves, buds, tender stems, adult tea leaves and tea aphid-damaged young leaves (ADYL) were studied by using an electroantennography (EAG) and a four-arm olfactometer. ACB elicited the largest EAG responses. Major volatile components, Z-3-hexen-1-ol, E-2-hexenal, n-hexanol, methyl salicylate and benzylalcohol, from the tea shoots were strongly EAG active. All the 4 tested tea shoot tissues also elicited significant EAG responses, with the young tea leaves being the strongest, followed by buds, tender stems and adult tea leaves. Surprisingly, ADYL elicited a weakly negative EAG response. In the olfactory assays, the fresh and tender tea leaves, as well as the individual major volatile components, e.g. Z-3-hexenyl acetate, methyl salicylate, E-2-hexen-1-ol and Z-3-hexen-1-ol, from the tender shoots (EAG-active) were all attractive. This result might indicate that the wingless tea aphids may use tea shoot volatiles as kairomone to find their optimal feeding sites, e.g. fresh tender tea shoots.     

Grandisol as an attractant for the sugar beet pest Bothynoderes affinis and data on other Lixinae species

As a result of field tests in Bulgaria and Hungary, cis‐2‐isopropenyl‐l‐methylcyclobutane ethanol (racemic grandisol) is reported for the first time as an attractant for Bothynoderes affinis (Schrank) (Coleoptera: Curculionidae, Lixinae), a member of the pest weevil complex of sugar beet. Dose–response experiments in the field using Csalomon TAL (modified pitfall) traps (Plant Protection Institute, CAR HAS, Budapest, Hungary) showed that catches of B. affinis adults increased with increasing attractant dose. In a subsequent experiment studying the effect of trap color (white, blue, yellow, fluorescent yellow, and transparent) all traps with the lure caught more than non‐baited control traps, and the highest number of adults was recorded in transparent and yellow baited traps. Trap color had a significant effect on the number of B. affinis females captured. Transparent TAL traps baited with 1–10 mg grandisol applied on rubber dispensers are recommended for the detection and monitoring of B. affinis. In addition to the target species, 17 other Lixinae species were captured during the field experiments, demonstrating for the first time the possible role of grandisol in the chemical communication systems of some of these species. A second locality of Lixus punctiventris Boheman (Lixinae, Lixini) in Bulgaria is reported. TAL traps baited with grandisol might be a useful tool for surveying Lixinae diversity in different biotopes.     

The topological differences between visitation and pollen transport networks: a comparison in species rich communities of the Himalaya–Hengduan Mountains

Pollination networks are usually constructed and assessed by direct field observations which commonly assume that all flower visitors are true pollinators. However, this assumption is often invalid and the use of data based on mere visitors to flowers may lead to a misunderstanding of intrinsic pollination networks. Here, using a large dataset by both sampling floral visitors and analyzing their pollen loads, we constructed 32 networks pairs (visitation versus pollen transport) across one flowering season at four elevation sites in the Himalaya–Hengduan Mountains region. Pollen analysis was conducted to determine which flower visitors acted as potential pollinators (pollen vectors) or as cheaters (those not carrying pollen of the visited plants). We tested whether there were topological differences between visitation and pollen transport networks and whether different taxonomic groups of insect visitors differed in their ability to carry pollen of the visited plants. Our results indicated that there was a significantly higher degree of specialization at both the network and species levels in the pollen transport networks in contrast to the visitation networks. Modularity was lower but nestedness was higher in the visitation networks compared to the pollen transport networks. All the cheaters were identified as peripheral species and most of them contributed positively to the nested structure. This may explain in part the differences in modularity and nestedness between the two network types. Bees carried the highest proportion of pollen of the visited plants. This was followed by Coleoptera, other Hymenoptera and Diptera. Lepidoptera carried the lowest proportion of pollen of the visited plants. Our study shows that the construction of pollen transport networks could provide a more in‐depth understanding of plant–pollinator interactions. Moreover, it suggests that detecting and removing cheater interactions when studying the topology of other mutualistic networks might be also important.     

Activity budget and spatial distribution of Bennett's wallabies (Macropus rufogriseus) in open versus closed exhibit designs

Although many studies investigating the impacts of zoo exhibit designs on captive animals exist, none have been performed on how they influence the behavior and welfare of captive Bennett's wallabies (Macropus rufogriseus). Here, we assess the impact of exhibit design on the activity budget and spatial distribution of Bennett's wallabies. We compared animal behavior in two open exhibits (i.e. physical interaction between animals and visitors permitted) to two closed exhibits (i.e. physical interaction between animals and visitors prohibited). Behavioral data were collected using focal sampling, and spatial distribution was recorded on exhibit maps at regular time intervals. We found a significant increase in feeding and interactive behaviors in closed exhibits in comparison to open exhibits. However, other behaviors such as resting, locomotion, and vigilance did not vary with design. Functional use of space was similar between both designs; however, the effect of habituation may be relevant to consider in future studies. Although some support for visitor effects were present, our study provided no evidence for strong impacts of exhibit design on Bennett's wallaby welfare. Our study emphasizes the need for additional research into the impacts of how zoo environments affect Bennett's wallaby behavior and welfare.