A study on the diversity of the moth community in the North Dagang Wetland Nature Reserve, Tianjin, China

North Dagang Wetland Nature Reserve is situated in the southeast of Tianjin, China. It is the biggest wetland nature reserve in Tianjin. An investigation into the diversity of the moth community was carried out from June 12 to October 14, 2001, and then from April 12 to October 30, 2002. The investigation was conducted in order to identify the moth species in wetlands, study their dynamic laws, select indicator insects to indicate wetland quality, and assist in the study and protection of wetlands. A total of 132 moth species were collected, which belonged to 105 genera in 17 families. The data about insects which was collected during the survey was listed and constructed in terms of species-abundance, indices of diversity (H′), evenness (J′), specific richness (S) and individual number (N) using the Microsoft Excel Program. The status of the wetlands was also analyzed using the moth community species-abundance curve, indices of diversity, the connection between evenness and richness indices, etc. The results show that moth species in the wetlands were not rich, and the moth community was unstable. In other words, the living environment of the moths and the environmental quality of the wetlands were unstable due to the serious degeneration of the wetland environment and human activities.     

Leaf variegation in Caladium steudneriifolium (Araceae): a case of mimicry?

The leaves of Caladium steudneriifolium (Araceae) of the understorey of a submontane rainforest in the Podocarpus National Park (South East Ecuador, 1,060 m a.s.l.) are plain green or patterned with whitish variegation. Of the 3,413 individual leaves randomly chosen and examined in April 2003, two-thirds were plain green, whereas one third were variegated (i.e., whitish due to absence of chloroplasts). Leaves of both morphs are frequently attacked by mining moth caterpillars. Our BLAST analysis based on Cytochrome-c-Oxidase-subunit-1 sequences suggests that the moth is possibly a member of the Pyraloidea or another microlepidopteran group. It was observed that the variegated leaf zones strongly resemble recent damages caused by mining larvae and therefore may mimic an attack by moth larvae. Infestation was significantly 4–12 times higher for green leaves than for variegated leaves. To test the hypothesis that variegation can be interpreted as mimicry to deter ovipositing moths, we first ruled out the possibility that variegation is a function of canopy density (i.e., that the moths might be attracted or deterred by factors unrelated to the plant). Then plain green leaves were artificially variegated and the number of mining larvae counted after 3 months. The results on infestation rate (7.88% of green leaves, 1.61% of the variegated leaves, 0.41% of white manipulated leaves and 9.12% of uncoloured manipulated leaves) suggest that ovipositing moths are deterred by the miner-infestation mimicry. Thus, variegation might be beneficial for the plants despite the implicated loss of photosynthetically active surface.     

Comparison of Yolk Production in Seven Pyralid Moth Species

Summary

The yolk proteins of six pyralid moths were analyzed and compared with the yolk proteins of Plodia interpunctella (Hübner). When cross-reacted in an Ouchterlony double immunodiffusion with antiserum raised to either total yolk proteins or purified vitellin from P. tnterpunctella, the yolk proteins of Anagasta kuehniella (Zeller), Cadra cautella (Walker), C. figulilella (Gregson), and Ephestia elutella (Hübner), closely related members of the subfamily Phycitinae, showed strong precipitation lines that consisted of four major yolk polypeptides (YPs). The yolk proteins from Amyelois transitella (Walker) were only weakly reactive, whereas yolk proteins from Galleria mel-lonella (L.) were not precipitated by either antiserum. Abdominal body walls (containing primarily fat body) from late pharate adult females were incubated in vitro and they secreted two major polypeptides that had molecular masses similar to the vitellogenins (YP1 and YP3) from P. interpunctella. In addition, ovarioles from late pharate adult females were incubated in vitro, and they secreted two major polypeptides that had molecular masses similar to YP2 and YP4 from P. interpunctella. When late pharate adult females were injected with ³⁵S-Met, the hemolymph of all species contained vitellogins that were secreted by their respective body walls in vitro. Ovarioles from injected females contained many labeled polypeptides, but there were four major bands that corresponded consistently to the vitellogenins secreted from the fat body and the two major polypeptides secreted from the ovarioles. These data show that the production of the major YPs in these closely related pyralid species is very similar, and that there is considerable conservation of immunological characters of yolk proteins in the subfamily Phycitinae.     

Spatial distribution,sampling efficiency and Taylor's power law. 2. Interpreting density-dependent sampling efficiency

1. The intimate relationship between sampling efficiency and Taylor's power law (TPL) was investigated with gypsy moth sample data. The data were used to compute sampling efficiency directly and indirectly by TPL.
2. Comparison of TPLs and efficiency plots of male and female pupae confirmed the identities linking TPL with sampling efficiency. Divergence of sex-specific TPL plots indicated local scale density-dependent sex ratio.
3. Egg mass sample data confirmed the sampling efficiency and TPL identities provided the same variance and mean vectors were used to compute TPLs. Small differences in sample numbers destroy the identities but approximate efficiency estimates are still obtainable from the TPLs. Sampling efficiency of timed walks, fixed area and variable area surveys were estimated and ranked.
4. Rescaling moth catches per trap to number per unit volume changes slope, intercept and correlation coefficient while stretching the pattern of data points. Comparison of absolute density estimates over two different time intervals showed density-dependent variation declining with increasing sample interval.
5. Fitting power laws by ordinary dependent regression is less efficient than fitting by geometric mean regression and produces biased regression parameters. The significance of this for the analysis and interpretation of ecological sample data generally is discussed.

     

Oviposition in Yponomeuta cagnagellus: the importance of contact cues for host plant acceptance

Small ermine moths (Yponomeutidae: Lepidoptera) are specialist herbivores. Species within the genus Yponomeuta are each specialized on a limited number of plant species, mainly within genera belonging to the Celastraceae. European Yponomeuta species have developed new specialized host affiliations, mainly on rosaceous hosts. Since these host shifts are reputed to be of consequence for speciation, the role of the ovipositing female is of particular interest. Study of the pre-oviposition behaviour of gravid Y. cagnagellus (Hb.) moths on host (Euonymus europaeus), non-host (Crateagus monogyna) and artificial oviposition substrates, provided information on the nature of the cues used for host plant acceptance and the insect’s perception of these cues. Host selection by adult females occurs with contact chemoreceptors probably located on the antennae or tarsi. MeOH-soluble, non-volatile phytochemical compounds washed from the host plant’s surface and applied on an artificial twig are sufficient to stimulate a complete sequence of behavioural elements leading to oviposition. Volatiles do not have a large effect on the pre-oviposition behaviour.     

Moth hearing on the Faeroe Islands, an area without bats

ABSTRACT. The ultrasound-sensitive ears found in several families of moths are believed to be part of a predator (bat) specific defence strategy; the moth's evasive responses, elicited by the calls of bats, reduce its chances of being caught. Bats have never been found on the Faeroe Islands, whereas moths migrated there before the last Ice Age, and have since been isolated from areas with bats. For this reason, the hearing characteristics of moths from the Faeroes are investigated in this study. All noctuid moths caught there have functional ears sensitive to ultrasound. Audiograms are determined for thirty-two individuals of four noctuid species: Cerapteryx gramminis L., Apamea crenata Hūfn., Apamea maillardi Gey. and Diarsia mendica F. The auditory characteristics of the moths from the Faeroes resemble those of moths from other temperate zones where bats are abundant. The audiograms revealed best frequencies between 20 and 45 kHz, relatively broad turnings (Q_10dB around 1), and thresholds of 35–50 dB SPL at the best frequency. The fact that the moths on the Faeroes possess such sensitive ears is explained by the large time spans which might be required for reduction of a character which is not directly opposed by a selection pressure.     

Intra- and interspecific sex-pheromone communication in the genus Yponomeuta

ABSTRACT. Male behaviour in pheromone attraction was observed in a wind tunnel for eight species of the genus Yponomeuta Latreille. Interspecific responses and the effect of some combinations of female pheromones were also investigated. The results show that the species Yponomeuta cagnagellus (Hübner), Y. malinellus Zeller, Y. rorellus (Hübner) and Y. plumbellus (Den. & Schiff.) are isolated by the specificity of their female pheromones. The other four species, Y. evonymellus (L.), Y. padellus (L.), Y. irrorellus (Hübner) and Y. vigintipunctatus (Retz.), exhibited interspecific pheromone attraction.     

Zigzagging and casting as a programmed response to wind-borne odour: a review

ABSTRACT. 'Counterturning' (meaning here the execution of a succession of alternating left and right turns) is the common feature in upwind zigzagging and cross-wind casting by flying insects manoeuvring towards a small source of wind-borne odour. Recent progress in understanding its control and function is discussed. Counterturning is internally controlled ('self-steered') in the limited sense that, once initiated by a chemical stimulus, it continues without further changes in the chemical input both in clean air and in a homogeneous cloud of odour. As a reaction it appears to be the kind of chemotaxis distinguished as longitudinal klinotaxis, for which the stimulus is a difference of chemical concentration detected over time along the insect's path, not across it. The new directions taken in response to the stimulus, being self-steered in the above sense, have no necessary relation to the direction of the chemical gradient that provided the stimulus but are influenced by the visual cues generated by wind drift. In wind, the counterturning programme is modulated by changes in the chemical input and simultaneously integrated with anemotaxis, but it can then continue in similar form after the wind has ceased. Unambiguous evidence for these conclusions is so far available only for certain flying male moths responding to sex pheromone. The primary function of counterturning, of all amplitudes and in both zigzagging and casting, appears to be the regaining of contact with an elusive scent.     

Negative effects of urbanisation on diurnal and nocturnal pollen-transport networks

Pollinating insects are declining due to habitat loss and climate change, and cities with limited habitat and floral resources may be particularly vulnerable. The effects of urban landscapes on pollination networks remain poorly understood, and comparative studies of taxa with divergent niches are lacking. Here, for the first time, we simultaneously compare nocturnal moth and diurnal bee pollen-transport networks using DNA metabarcoding and ask how pollination networks are affected by increasing urbanisation. Bees and moths exhibited substantial divergence in the communities of plants they interact with. Increasing urbanisation had comparable negative effects on pollen-transport networks of both taxa, with significant declines in pollen species richness. We show that moths are an important, but overlooked, component of urban pollen-transport networks for wild flowering plants, horticultural crops, and trees. Our findings highlight the need to include both bee and non-bee taxa when assessing the status of critical plant-insect interactions in urbanised landscapes.