Spatial fragrance patterns in flowers of Silene latifolia: Lilac compounds as olfactory nectar guides?

Floral odour can differ qualitatively and quantitatively between different parts of the flowers, and these spatial fragrance patterns within the flowers can be used by pollinators for orientation on flowers. Here we present results of spatial fragrance patterns within flowers of the dioecious Silene latifolia (Caryophyllaceae). Volatiles were collected and analysed using a highly sensitive dynamic headspace method, which allows dramatically reducing the sample time. From all flower parts, especially the petals and the anthophore emitted the typical flower volatiles of S. latifolia. However, compounds emitted from the petals differed from compounds emitted by the anthophore. The anthophore emitted the monoterpenoids lilac aldehydes and alcohols, whereas, all other typical scent compounds (e.g. benzoids, other monoterpenoids) were emitted by the petals. Lilac aldehydes are known to be behaviourally very attractive for noctuid moths, and they may serve as nectar guides in S. latifolia.     

Plant species richness as the main driver of moth metacommunities

1. Ecologists have recognised several factors that may explain the distribution of species in a metacommunity. These factors may be related to the dispersal of individuals among the patches and environmental conditions. 2. Here, we attempted to determine which of the four different metacommunity frameworks (patch dynamics, mass effect, neutral processes, and species sorting) explain the distribution of Arctiinae moths in Brazilian savanna areas with different tree species richness. 3. The Arctiinae moths were categorised as habitat specialists or generalists, common or rare, and belonging to the tribes Arctiini and Lithosiini. We hypothesized that environmental variables best explain the abundance and occurrence of habitat specialist species, common species, and members of Lithosiini; whereas spatial processes are more closely related to habitat generalists, rare species, and members of Arctiini. 4. Contrary to our expectations, we found that the species sorting (mainly dictated by the species richness of trees) best explained the variation in abundance and occurrence of the majority of species groups. Spatial processes (more related to patch dynamics, mass effect, and neutral), although they were significantly related to some species groups, were not strong enough to explain the distribution of these species in the study area. 5. The plant species richness was the most important environmental condition, related to moth species niches. Therefore, species sorting best explained the distribution of the species of Arctiinae in the Brazilian savanna.     

Construction,validation, and application of nocturnal pollen transport networks in an agro‐ecosystem: a comparison using light microscopy and DNA metabarcoding

1. Moths are globally relevant as pollinators but nocturnal pollination remains poorly understood. Plant–pollinator interaction networks are traditionally constructed using either flower‐visitor observations or pollen‐transport detection using microscopy. Recent studies have shown the potential of DNA metabarcoding for detecting and identifying pollen‐transport interactions. However, no study has directly compared the realised observations of pollen‐transport networks between DNA metabarcoding and conventional light microscopy. 2. Using matched samples of nocturnal moths, we constructed pollen‐transport networks using two methods: light microscopy and DNA metabarcoding. Focussing on the feeding mouthparts of moths, we developed and provide reproducible methods for merging DNA metabarcoding and ecological network analysis to better understand species interactions. 3. DNA metabarcoding detected pollen on more individual moths, and detected multiple pollen types on more individuals than microscopy, although the average number of pollen types per individual was unchanged. However, after aggregating individuals of each species, metabarcoding detected more interactions per moth species. Pollen‐transport network metrics differed between methods because of variation in the ability of each to detect multiple pollen types per moth and to separate morphologically similar or related pollen. We detected unexpected but plausible moth–plant interactions with metabarcoding, revealing new detail about nocturnal pollination systems. 4. The nocturnal pollination networks observed using metabarcoding and microscopy were similar yet distinct, with implications for network ecologists. Comparisons between networks constructed using metabarcoding and traditional methods should therefore be treated with caution. Nevertheless, the potential applications of metabarcoding for studying plant–pollinator interaction networks are encouraging, especially when investigating understudied pollinators such as moths.     

Evidence for short-range sonic communication in lymantriine moths

Sexual communication of nun moth, Lymantria monacha (L.), pink gypsy moth, Lymantria mathura Moore, and fumida tussock moth, Lymantria fumida Butler (all Lepidoptera: Noctuidae: Lymantriinae), is known to be mediated by pheromones. We now show that males are attracted by the sounds of conspecific females over short distances and that wing fanning male and female L. monacha, L. mathura and L. fumida produce species- and sex-specific wing beat and associated click sounds that could contribute to reproductive isolation. Evidence for short-range communication in these lymantriines includes (i) scanning electron micrographs revealing metathoracic tympanate ears, (ii) laser interferometry showing particular sensitivity of tympana tuned to frequency components of sound signals from conspecifics, and (iii) phonotaxis of male L. monacha and L. fumida to speakers playing back sound signals from conspecific females. We conclude that tympanate ears of these moths have evolved in response not only to bat predation, but also for short-range mate finding and possibly recognition.     

Description of nine new species of Heliura Butler from South America (Lepidoptera,Erebidae, Arctiinae,Arctiini, Ctenuchina)

Nine new species of the genus Heliura are described from Brazil (H. brasiliana sp. nov., H. olivocolora sp. nov., H. pulcherrima sp. nov., and H. laerteae sp. nov.), Ecuador (H. ecuadoris sp. nov.), Peru (H. flavipennis sp. nov. and H. peruana sp. nov.), and Venezuela (Heliura albiventris sp. nov. and H. juliani sp. nov.). They are illustrated in habitus and genitalia, and their phylogenetic affinities are discussed based on morphological evidence.     

A new genus of primitive Nepticulidae (Lepidoptera) from eastern Australia, with a revised diagnosis of nepticulid subfamilies

Roscidotoga, a new genus of Nepticulidae, is described. Three new species– R. callicomae, R. eucryphiae and R. sapphiripes –are described, all from rainforest in eastern Australia. Adults, genitalia, larvae, pupal exuviae and mines are illustrated. The larvae are leaf-miners on the Gondwanan plant families Cunoniaceae, Eucryphiaceae and Elaeocarpaceae. The systematic position of the genus is discussed: it is assigned to the subfamily Pectinivalvinae and considered to represent the sister-group of Pectinivalva Scoble, which likewise appears to be endemic to Australia. A revised diagnosis of the two nepticulid subfamilies is presented.     

Motivation models fail to explain oviposition behaviour in the diamondback moth

Abstract. It is widely accepted that previous experience and internal physiological factors (such as egg‐load) affect host‐plant discrimination during oviposition by phytophagous insects. However, there is some debate as to how these factors interact in a mechanistic sense to control acceptance. The role of learning and host deprivation in host acceptance by adult diamondback moths (Plutella xylostella L.) was investigated. In the first experiment, we tested whether experience of a lower ranked host cabbage increased acceptance of a higher ranked host as predicted by a hierarchy threshold model. Moths trained on cabbage were over three times more likely to accept cabbage during testing than untrained moths. There was no effect of cabbage training on acceptance of cress, indicating that the effect of training was species‐specific. In a second experiment, designed to test the prediction of motivation models that insects become less discriminating when deprived of oviposition opportunities, depriving females of host plants for 2 nights significantly increased female egg‐load (×2.3). Host deprivation did not decrease discrimination between the preferred host cress and cabbage. Cabbage and cress plants were equally likely to have been accepted by nondeprived moths after 1 night of exposure, yet moths deprived of hosts for 2 nights strongly preferred cress when tested during the first 20 min of the scotophase. During this 20‐min period, previous host deprivation increased acceptance of host plants generally but did not decrease discrimination between hosts. These data contradict the expectation that there is an inverse relationship between host species discrimination and the failure of an insect to find hosts as found in existing oviposition acceptance models. As an alternative, the Incremental Acceptance Model of host acceptance behaviour is presented, in which responsiveness to a host is a function of the recent encounter rate with host‐specific stimuli, and the oviposition reflex is regulated by nonspecific cues such as egg‐load.     

Phylogenetic analysis of Zygaenoidea small-subunit rRNA structural variation implies initial oligophagy on cyanogenic host plants in larvae of the moth genus Zygaena (Insecta: Lepidoptera)

Cyanogenesis, the release of toxic cyanide from living cells, plays an important role in the defence system of certain plant (e.g. Fabaceae) and animal (e.g. Zygaenidae) taxa. The larvae of a significant number of Zygaena moth species (Zygaenidae) preferentially feed on cyanogenic Fabaceae and some of them are able to sequester cyanogenic compounds of their host plants. Using secondary structure variation of the small-subunit rRNA, we tested the currently accepted evolutionary hypothesis explaining species diversification in the genus Zygaena . We derived secondary structures considering evidence from covariation patterns and thermodynamic folding and applied structural information in a phylogenetic analysis. Contrary to previous assumptions, our results suggest that the use of cyanogenic larval host plants is an ancient trait and that the ability to feed on cyanogenic plants was probably already present in the most recent common ancestor of Zygaena . The utilization of acyanogenic plants in Zygaena species appears to be the result of a single secondary, reverse, larval host-plant shift. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 367–381.     

Pollination by nocturnal Lepidoptera,and the effects of light pollution: a review

1. Moths (Lepidoptera) are the major nocturnal pollinators of flowers. However, their importance and contribution to the provision of pollination ecosystem services may have been under‐appreciated. Evidence was identified that moths are important pollinators of a diverse range of plant species in diverse ecosystems across the world. 2. Moth populations are known to be undergoing significant declines in several European countries. Among the potential drivers of this decline is increasing light pollution. The known and possible effects of artificial night lighting upon moths were reviewed, and suggest how artificial night lighting might in turn affect the provision of pollination by moths. The need for studies of the effects of artificial night lighting upon whole communities of moths was highlighted. 3. An ecological network approach is one valuable method to consider the effects of artificial night lighting upon the provision of pollination by moths, as it provides useful insights into ecosystem functioning and stability, and may help elucidate the indirect effects of artificial light upon communities of moths and the plants they pollinate. 4. It was concluded that nocturnal pollination is an ecosystem process that may potentially be disrupted by increasing light pollution, although the nature of this disruption remains to be tested.