A key to the Mexican and Central America Genera of Anthonomini (Curculionidae,Curculioninae)

Presently the only keys available for identification of genera of Anthonomini are limited to those of the United States of America and Canada. A dichotomous key is presented to identify all genera of Mexican and Central American Anthonomini. Previous keys do not include the genera Achia, Botanebius, Loncophorus, Loncophorellus and Melexerus. A brief synopsis is given for each genus and photographs of representative species are included.     

Initiation and characterization of five embryonic cell lines from the cotton boll weevil anthonomus grandis in a commercial serum- free medium

Summary Five continuous cell lines were initiated from embryonic tissue of the cotton boll weevilAnthonomus grandis Boheman in a commercially available, serum-free medium (Excell 401) and have undergone in excess of 60 passages. Isoenzyme analysis confirmed that the lines originated from boll weevil tissue. Four of the lines grew as single attached cells of either epithelioid or fibroblastoid morphology. The fifth line, BRL-AG-2, grew primarily as cell aggregates and was found to release ecdysteroids (primarily ecdysone) into the culture medium. Evidence was also obtained suggesting that line BRL-AG-2 synthesizes chitin. Three lines, BRL-AG-1, BRL-AG-3A, and BRL-AG-3C, could be induced to produce an antibacterial factor(s) which was released into the culture medium.     

Range expansion of the small spruce bark beetle Ips amitinus: a newcomer in northern Europe

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Irrigation and its effect on polyphagous shot hole borer attack

Polyphagous shot hole borer (PSHB), Euwallacea whitfordiodendrus (Schedl) (Coleoptera: Curculionidae, Scolytinae), is an ambrosia beetle that has recently invaded southern California, USA. This beetle successfully attacks and reproduces in a multitude of tree species. As direct control methods are limited, we investigated cultural management options, and sought to determine whether irrigation affects the number of attacks host trees experienced. If irrigation plays a role, cultural control methods could be recommended to managers and growers. Three separate experiments were conducted that monitored the number of attacks on trees with different levels of irrigation. Two experiments examined PSHB attacks in established landscape trees where irrigation was either present or absent. A third experiment used young potted box elder with irrigation controlled with timed emitters. In all three experiments, the level of irrigation received by the trees did not affect the number of attacks. The results suggest that changes in irrigation practices do not affect risk from PSHB attack.     

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.     

Spatial analysis of Listronotus maculicollis immature stages demonstrates strong associations with conspecifics and turfgrass damage but not with optimal hosts on golf course fairways

For insects that develop on few hosts and/or have immobile immature stages, optimal oviposition theory suggests that females should seek high‐quality hosts that maximize larval development and reduce competition from conspecifics. However, there is a growing amount of evidence that suggests female choice may often be at odds with their offspring's development. Listronotus maculicollis (Kirby) (Coleoptera: Curculionidae) is a serious pest of golf course turfgrass in eastern North America. The weevil develops on few hosts and demonstrates improved fitness traits when developing on Poa annua L. (Poaceae). However, previous population studies observed either weak or no correlations between the spatial dispersion of larval populations and P. annua in the field. In this study, populations on three golf course fairways were monitored over a 4‐year period (2009–2012) to determine whether the lack of spatial associations between preferred hosts and immatures was a result of spatial scale or the density and distribution of conspecifics. Spatial Analysis by Distance IndicEs (SADIE) was used to characterize the spatial dispersion of populations of individual stages (larvae and pupae), P. annua, and turfgrass damage. Life stages were aggregated in each observation, independent of population density or the spatial dispersion of hosts. The distribution of consecutive and non‐consecutive immature stages was found to be correlated in all years, suggesting that females do not avoid patches already occupied by conspecific eggs. Surprisingly, significant spatial associations were not found between larvae and P. annua when the host plant was relatively abundant. Hence, multiple mechanisms may drive L. maculicollis oviposition site‐selection behavior, and a flexible strategy may allow the weevil to persist in areas where P. annua is not the dominant species. Future studies are required to determine what other factors (e.g., natural enemy‐free space, egg or time limitations) influence oviposition behavior.     

The structure of feeding behavior in a phytophagous insect (Hylobius abietis)

Analysis of the feeding behavior of animals using such a high temporal resolution that meals can be defined may improve our understanding of the mechanisms regulating feeding. Meals can be distinguished in an ethologically meaningful manner by using the ‘meal criterion’, the shortest non‐feeding interval between feeding bouts recognized as meals. However, such a criterion has only been determined for a few insect species. Applying a recent method developed for assessing meal criteria for vertebrates, we determined the meal criterion for Hylobius abietis (L.) (Coleoptera: Curculionidae) based on data from video recordings of single individuals feeding on seedlings of Norway spruce, Picea abies (L.) Karst. (Pinaceae). The pine weevil is an economically important pest insect, because it feeds on the stem bark of planted conifer seedlings. Weevils had 4–5 meals per day. Each meal lasted about 24 min during which about 13 mm² of bark per meal were removed. Females had longer total meal durations and longer non‐feeding intervals within meals than males. Girdling seedlings did not affect the weevils' feeding properties. The size of meals was significantly correlated with the duration of non‐feeding intervals before and after them. This study is one of few describing the feeding behavior of an insect at a temporal resolution that allows individual meals to be distinguished. With more meal‐related data from insects available, differences in meal properties may be interpreted based on phylogeny, ecology, and physiology. Our results may also assist in the setup and interpretation of studies of plant‐insect interactions, and facilitate the evaluation and development of methods to protect plants against herbivores.     

Attraction of pepper weevil to volatiles from damaged pepper plants

Pioneer herbivorous insects may find their host plants through a combination of visual and constitutive host‐plant volatile cues, but once a site has been colonized, feeding damage changes the quantity and quality of plant volatiles released, potentially altering the behavior of conspecifics who detect them. Previous work on the pepper weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae), demonstrated that this insect can detect and orient to constitutive host plant volatiles released from pepper [Capsicum annuum L. (Solanaceae)]. Here we investigated the response of the weevil to whole plants and headspace collections of plants damaged by conspecifics. Mated weevils preferred damaged flowering as well as damaged fruiting plants over undamaged plants in a Y‐tube olfactometer. They also preferred volatiles from flowering and fruiting plants with actively feeding weevils over plants with old feeding damage. Both sexes preferred volatiles from fruiting plants with actively feeding weevils over flowering plants with actively feeding weevils. Females preferred plants with 48 h of prior feeding damage over plants subjected to weevil feeding for only 1 h, whereas males showed no preference. When attraction to male‐ and female‐inflicted feeding damage was compared in the Y‐tube, males and females showed no significant preference. Wind tunnel plant assays and four‐choice olfactometer assays using headspace volatiles confirmed the attraction of weevils to active feeding damage on fruiting plants. In a final four‐choice olfactometer assay using headspace collections, we tested the attraction of mated males and virgin and mated females to male and female feeding damage. In these headspace volatile assays, mated females again showed no preference for male feeding; however, virgin females and males preferred the headspace volatiles of plants fed on by males, which contained the male aggregation pheromone in addition to plant volatiles. The potential for using plant volatile lures to improve pepper weevil monitoring and management is discussed.     

Contrasting floral biology of Artabotrys species (Annonaceae): Implications for the evolution of pollinator trapping

Artabotrys comprises a species-poor early divergent grade (EDG) and a main species-rich clade (“main Artabotrys clade,” MAC). All members of the MAC exhibit a remarkably well-conserved floral Bauplan characterized by a tightly enclosed floral chamber with an elaborate rim between the inner petal blade and claw. Conversely, EDG resembles the sister genus Xylopia in lacking the inner petal rim, with one species (Artabotrys brachypetalus) bearing petals that lack the distinction between blade and claw altogether. The floral phenology and pollination ecology of two exemplar species—Artabotrys brachypetalus from the EDG and Artabotrys blumei from the MAC—are compared, including assessment of effective pollinators and their activity patterns, scent chemistry and thermogenesis. Our study revealed that Artabotrys blumei exhibits abbreviated anthesis (c. 27 hr), with a floral phenology and morphology that are clearly consistent with pollinator trapping, and may be pollinated by small beetles. Artabotrys brachypetalus has a typical anthetic duration (c. 45 hr), lacks a pollinator trapping mechanism, and is pollinated by honey bees and curculionid beetles. The “xylopioid” traits of the EDG are likely to be plesiomorphic, whereas the tightly enclosed floral chamber is likely to be apomorphic for the MAC and functionally significant in trapping pollinators.     

Feeding by short-snouted weevils on seedlings of seven tree species planted beneath Norway spruce at differing stand densities

1 Short-snouted weevils, including Strophosoma spp. and related species, may damage tree seedlings. We investigated the damage caused by these weevils feeding on seedlings of seven tree species planted in clear-cuts and under shelterwoods with three densities (control, dense, and sparse).
2 There were no pronounced differences in damage caused by short-snouted weevils in the various shelterwood densities. Most feeding occurred in the clear-cuts during the first year, whereas more seedlings were damaged in the shelterwoods of all densities in the second year. In the third year, virtually no feeding occurred in either the clear-cuts or shelterwoods. We cannot explain this pattern of damage, but a fallow period of 2 years seems to prevent short-snouted weevil damage.
3 We determined the general feeding preferences for short-snouted weevils to be cherry, lime > beech, oak, spruce > maple, ash. However, although Strophosoma mellanogrammum [Correction added after online publication 8 December 2008: Strophosoma melanogrammum corrected to Strophosoma mellanogrammum ] was observed feeding on seedlings, no full short-snouted weevil inventory was conducted, so caution must be exercised when drawing conclusions from this study regarding weevil damage patterns and feeding preferences.
4 Short-snouted weevils can sometimes occur in large numbers and may destroy entire reforestation projects, but in our study their influence on seedling growth and survival was minor.