Population dynamics and parasitism rate of leafhopper species (Hemiptera: Cicadellidae) in maize (Zea mays L.) crop

Maize is an important crop in Turkey that is infested by various leafhopper species during the whole season. Monitoring population dynamics and parasitism rate of these species would help to devise effective management practices. This study determined population dynamics of four leafhopper species, i.e., Zyginidia sohrab Zachvatkin, 1947, Empoasca decipiens Paoli, 1930 and Psammotettix striatus (Linnaeus, 1758) in second maize crop. Similarly, population dynamics and parasitism rate of egg parasitoid (Anagrus atomus) of these leafhopper species was also studied through July to November 2018 in Akçakale, Harran and Haliliye districts of Şanlıurfa province, Turkey. Population density of all species significantly varied among studied districts with the highest density of A. atomus recorded on 7 September with 30 adults/trap in Haliliye district. The parasitism rate on Z. sohrab eggs was 78% in Akçakale, 82% in Harran and 63% in Haliliye district. It was followed by E. decipiens with 18% in Akçakale, 14% in Harran and 32% in Haliliye. The highest population density of Z. sohrab was recorded on 21 September in Akçakale (4328 adults/trap), Harran (3920 adults/trap) and Haliliye (4592 adults/trap). Similarly, E. decipiens had the highest (1216 adults/trap) population density on 10 August in Harran, 12 October (368 adult/trap) in Akçakale and 17 August (2184 adults/trap) in Haliliye. Population dynamics of leafhoppers and their egg parasitoid coincided with each other. The parasitism rate was lower than other provinces in Turkey which is owed to high pesticide use in Şanlıurfa province. Therefore, chemical control should be decided by considering population development of beneficial insect species.

Beneficial insects are associated with botanically rich margins with trees on small farms

Beneficial insect communities on farms are influenced by site- and landscape-level factors, with pollinator and natural enemy populations often associated with semi-natural habitat remnants. They provide ecosystem services essential for all agroecosystems. For smallholders, natural pest regulation may be the only affordable and available option to manage pests. We evaluated the beneficial insect community on smallholder bean farms (Phaseolus vulgaris L.) and its relationship with the plant communities in field margins, including margin trees that are not associated with forest fragments. Using traps, botanical surveys and transect walks, we analysed the relationship between the floral diversity/composition of naturally regenerating field margins, and the beneficial insect abundance/diversity on smallholder farms, and the relationship with crop yield. More flower visits by potential pollinators and increased natural enemy abundance measures in fields with higher plant, and particularly tree, species richness, and these fields also saw improved crop yields. Many of the flower visitors to beans and potential natural enemy guilds also made use of non-crop plants, including pesticidal and medicinal plant species. Selective encouragement of plants delivering multiple benefits to farms can contribute to an ecological intensification approach. However, caution must be employed, as many plants in these systems are introduced species.

Consumer-Ready Insect Hotels: An Assessment of Arthropod Visitation and Nesting Success

Insect nesting boxes and hotels have the potential to provide shelter and overwintering sites for beneficial insect communities such as pollinating bees, wasps, earwigs, and other predatory arthropods. This study evaluated beneficial arthropod visitation to consumer-ready, commercially available nesting boxes over a 2-yr period. Insect hotels were placed on mature river birch (Betula nigra L.) and crape myrtle (Lagerstroemia indica L.) in garden plots established with floral resources for pollinators and other beneficial insects. Paper and thread-waisted wasps, soldier flies, predatory ants, and spiders were observed visiting the boxes. Boxes located in garden plot treatments (with floral resources) had the greatest numbers and diversity of pollinator and beneficial insect taxa compared to control plot treatments (naturalized areas away from floral resources) in 2016. Insect hotels placed on B. nigra had a higher number of thread-waisted wasps in 2016 and spiders and total beneficial insects in 2017. Higher numbers of predatory ants and total beneficial arthropods were found in boxes placed on L. indica in 2016. During the study, bamboo stems and drilled tunnels in the insect boxes were evaluated for arthropod inhabitance. Largest counts of occupied stems and tunnels were observed in boxes placed in proximity to floral resources and on L. indica trees.

Floral Plantings in Large-Scale Commercial Agroecosystems Support Both Pollinators and Arthropod Predators

Beneficial insect populations and the services that they provide are in decline, largely due to agricultural land use and practices. Establishing perennial floral plantings in the unused margins of crop fields can help conserve beneficial pollinators and predators in commercial agroecosystems. We assessed the impacts of floral plantings on both pollinators and arthropod predators when established adjacent to conventionally managed commercial potato fields. Floral plantings significantly increased the abundance of pollinators within floral margins compared with unmanaged margins. Increased floral cover within margins led to significantly greater pollinator abundance as well. The overall abundance of arthropod predators was also significantly increased in floral plantings, although it was unrelated to the amount of floral cover. Within adjacent potato crops, the presence of floral plantings in field margins had no effect on the abundance of pollinators or predators, although higher floral cover in margins did marginally increase in-crop pollinator abundance. Establishing floral plantings of this kind on a large scale in commercial agroecosystems can help conserve both pollinators and predators, but may not increase ecosystem services in nearby crops.

Arthropoda yang Berasosiasi dengan Tanaman Refugia pada Pertanaman Padi di Desa Besur, Kabupaten Lamongan, Jawa Timur

Rice farmers in Besur Village planted four species of refugia plants around rice plants to enhance biological control as a part of Healthy Plant Management Program. These refugia plants were flowering plants i.e., Cosmos sulphureus, Helianthus annuus, Zinnia elegans, and Sesamum indicum. The objective of this research was to observe the Arthropods associating with these refugia plants. This research was conducted in December 2017 to March 2018 at Besur Village, Lamongan District, East Java Province. Samples were obtained from each refugia species by branches beating, sweep net, pitfall trap, and direct observation method in the vegetative, generative, and postharvest periods paddy plant. The results showed that Arthropods associated with refugia plants are mostly belong to the order of Diptera, Hymenoptera, and Araneae. Detritivore group was the most abundant in all periods. Analysis of the diversity and similarity of all refugia species showed moderate to high values with high similarities each other. Keywords: beneficial insect, flower, healthy plant management, integrated pest management, paddy field

Increased accuracy of signaling by hyperbolic odorant mixtures in a beneficial insect-plant relationship

Animals use odors in many natural contexts, for example, for finding mates or food, or signaling danger. Analyses of natural odors search for either the most meaningful components of a natural odor mixture, or they use linear metrics to analyze the mixture compositions. Both analyses assume that the odor space itself is Euclidian, like visual and auditory spaces. However, we have recently shown that the physical space for complex mixtures is ‘hyperbolic’ – curved – because of the correlations that arise in biosynthetic pathways. Here we shown that the shape of the space for flowers (Brassica rapa) using an existing data set can also be better described with a hyperbolic rather than a linear shape, and that components in the space correlate to the nectar and pollen resource sought by bee pollinators. We also show that honey bee and bumble bee antennae can detect most components of the B. rapa odor space. We argue that further investigation of the implications of hyperbolic space can have important implications for how sensory systems have evolved to encode the space.

Influence of colour on oviposition behaviour in green lacewing Chrysoperla zastrowi sillemi (Esben - Petersen) (Neuroptera: Chrysopidae)

The Green lacewing, Chrysoperla zastrowi silleni (Esben-Peterson), also known as “aphidlion” is a beneficial insect predator of various insect pests. The laboratory experiment was conducted during 2018-19 to evaluate the substrate colour preference for egg laying by C. zastrowi sillemi. Egg receiving sheets were pasted with white, black, green, indigo blue, yellow, brown, violet, sky blue, pink, red and orange colour papers. Among all colours C. z. sillemi females preferred orange colour as a substrate for egg laying with maximum number of eggs (43.13/female/day) followed by red colour substrate (25.50 eggs/female/day). White and black were least preferred.