Ecological Entomology

doi: 10.1111/een.13166pmid: N/A

Miyazaki, Nanako; Yamamoto, Tetsuya; Hattori, Mitsuru

doi: 10.1111/een.13244pmid: N/A

To feed on prey efficiently, predators must overcome the prey's defensive traits. However, there are fewer reports on the antagonistic traits of predators than there are on the defensive traits of prey. Here, we focus on prey–predator interactions between social aphids and aphidophagous lepidopteran larvae. Larvae of Taraka hamada (Lepidoptera: Lycaenidae) are specialist predators of the social aphid Ceratovacuna japonica (Homoptera: Aphididae), and later instar larvae have long lateral body setae. Because this aphid produces defensive individuals (soldiers), we hypothesised that T. hamada larvae have an antagonistic trait that prevents attacks by soldiers and tested whether that trait might be their lateral body setae. To test whether a larva's lateral body setae constitute an antagonistic trait against the soldier's physical defence, we compared the rate of aphid consumption per unit time and the vulnerability to attack by soldiers between larvae with short lateral body setae and larvae with long lateral body setae in the presence of soldiers. Our results showed that the aphid consumption rate of larvae with long lateral body setae was significantly higher than that of larvae with short lateral body setae. Furthermore, the larvae with short lateral body setae were more vulnerable to soldier attacks than the larvae with long lateral body setae. These results imply that the length of the lateral body setae of T. hamada larvae affects their vulnerability to soldier attacks and that the lateral body setae are an antagonistic trait against the soldiers of this social aphid.

Prouty, Cody; Bartlett, Lewis J.; Krischik, Vera; Altizer, Sonia

doi: 10.1111/een.13245pmid: N/A

Numerous studies have documented the negative effects of neonicotinoids on bees; it remains crucial to examine how neonicotinoids affect other non‐target nectar‐feeding insects, such as the monarch butterfly, Danaus plexippus. Wildflowers growing near agricultural areas can be contaminated with neonicotinoids that affect survival or cause sublethal changes to behaviours of nectar‐feeding insects. Nectar residues of imidacloprid and clothianidin found in milkweeds and wildflowers adjacent to agricultural field range from 0 to 72.8 ng/mL. At field‐relevant doses, two neonicotinoids (imidacloprid and clothianidin) were studied for their effects on adult monarch survival, reproduction, flight and behaviour. First, we fed adult monarchs artificial nectar solutions ranging from 15 to 386 ng/mL of imidacloprid and 19 to 531 ng/mL of clothianidin. Neonicotinoid ingestion slightly reduced monarch reproduction but had no significant effects on survival, weight change, or activity levels. Second, we fed monarchs higher clothianidin doses (909 and 4030 ng/mL), that exceed field‐relevant levels by 22 and 99 times. These higher doses reduced monarch nectar consumption, survival, flight performance and reaction time in response to a drop test. Results show that adult monarchs tolerate field‐relevant doses as high as 54 ng/mL for imidacloprid and 75 ng/mL for clothianidin, with minimal lethal or sub‐lethal effects until much higher doses are supplied. We conclude that adult monarchs are more tolerant of ingested clothianidin and imidacloprid than indicated by previous research.

Lunde, Lisa F.; Ferkingstad, Bendik; Wegger, Hermann; Høye, Toke T.; Mann, Hjalte M. R.; Birkemoe, Tone

doi: 10.1111/een.13246pmid: N/A

Fungi and invertebrates comprise a major part of biodiversity in dead wood ecosystems and invertebrates depend on fungi to utilise the dead wood resource. Many invertebrates also visit the long‐lived fruit bodies of wood‐decay fungi to feed on spores, the hymenium or other invertebrates. However, as traditional sampling methods are labour‐intensive, we know little of these interactions. In this study, we use time‐lapse cameras to monitor invertebrates visiting the hymenium of a common wood‐decay fungus, Fomitopsis pinicola, and explain their activity in terms of temporal variation, temperature and presence of Gyrophaena boleti, a highly abundant fungivorous beetle living primarily in fruit bodies of F. pinicola. The most common invertebrates on F. pinicola fruit bodies were Coleoptera, Araneae, Diptera, Gastropoda and Chilopoda. The invertebrate activity exhibited strong temporal variation with higher abundance during night and, for Coleoptera, earlier in the season. We discuss how this might correlate with the sporulation period of F. pinicola. The presence of G. boleti had a positive impact on the predatory Lordithon lunulatus and Ipidia binotata, and a negative impact on the fungivorous Thymalus limbatus and Peltis ferruginea. Chilopoda and L. lunulatus were ephemeral visitors, while the fungivorous Coleoptera and Araneae stayed the longest. We estimated the invertebrates' visitation frequency and duration, which would be time‐consuming to obtain with traditional methods. We offer improvements to our method and urge future research on invertebrate–fungus interactions to quantify invertebrate visits to fungal fruit bodies.

Fachinetti, Romina; Grilli, Mariano P.

doi: 10.1111/een.13247pmid: N/A

Landscape ecology studies are based on the concept that most local phenomena cannot be completely understood without considering the role of the surrounding landscape. A key factor in landscape ecology is the heterogeneous distribution of resources that different species use for food and reproduction. In this paper, we analyse the role of patch quality together with landscape attributes on the distribution and abundance of Arhopalus rusticus in the central west of Córdoba Province in Argentina. Land cover was estimated using Landsat 8 scenes. Landscape was quantified by estimating the focal patch area, the distance to nearest pine patch and the quality of the patch through the enhanced vegetation index obtained from the MODIS satellite. Generalised linear mixed models were employed to analyse the relationship between the independent variables and A. rusticus abundance. A multi‐model inference approach was employed to select the best model. The distance to nearest pine patch and the enhanced vegetation index of the previous year showed a negative relationship with A. rusticus abundance, while the relationship with the focal patch area and the enhanced vegetation index of the year in which the sampling took place was positive. Our results show that although landscape pattern of pine patches affects the invading capability of A. rusticus in a direct way, the forest patch quality is an important factor that limits the capability of the insect to establish itself in an area.

Ortega, M.; Matallanas, B.; Ricarte, A.; Pascual, S.

doi: 10.1111/een.13248pmid: N/A

Sustainability of agroecosystems depends on the ecosystem services, provided by beneficial organisms, such as the syrphids (Diptera: Syrphidae) acting as other‐insect predators and pollinators in different crops. In the case of olive groves, syrphids are predators of important pests and are endangered by the continuous intensification of agriculture, including landscape simplification. In this work, the effect of landscape structure on the abundance and species richness of syrphids in the olive agroecosystem of central Spain is assessed. Adult syrphids were sampled in 2015 and 2016 in the centre of circular areas of 15 olive grove landscapes (from 250 to 1500 m radius) representing a gradient of landscape complexity, in the province of Madrid, central Spain. The syrphid assemblage was made up of 57 species, although Eupeodes corollae, Eristalis tenax, Eristalis similis and Chrysotoxum intermedium made up 76% of the captures. Syrphid abundance and species richness were favoured in complex landscapes, with low olive grove area (CAO). Other landscape indices showed also this trend although their effect was not as strong and consistent as that of CAO. The area of scrublands (CAS) favoured syrphids in spring, but was unfavourable in autumn. The effect of Shannon's Evenness Index (SHEI) and mean shape index (MSI) was less consistent. The effect of CAO increased with increasing buffers radii, while the effect of CAS, SHEI and MSI was detected in general at smaller radii, indicating these indices affect different processes. Redundancy analysis (RDA) detected some differences between species regarding their abundance in spring versus autumn, and their relationship with landscape indices. This work provides new evidence that maintenance of complex landscapes is essential for maintaining functional biodiversity in the olive agroecosystem.

Ebada, Ali; de Roode, Jacobus C.; Majewska, Ania A.

doi: 10.1111/een.13255pmid: N/A

Few studies have described the effects of larval diet quality on adult insect flight performance. Flight muscle development and high‐powered flight in insects are associated with costly energetic demands. Because larval diet is the energy source that powers these mechanisms, we asked whether larval diet has an impact on flight performance and metabolism in the monarch butterfly (Danaus plexippus Linnaeus). Monarch caterpillars from the eastern North American and Puerto Rican populations were fed a diet of either Asclepias incarnata L. (native to the eastern North American population) or Asclepias curassavica L. (native to the Puerto Rican population and uncommon in eastern North America). We flew the monarchs on a tethered flight mill to acquire flight performance metrics including velocity, distance, duration, power, and oxygen consumption rate. Monarchs reared on the A. incarnata L. milkweed showed slower, shorter, and less powerful flights than those fed on A. curassavica L. However, eastern North American and Puerto Rican monarchs, which were reared under summer conditions, did not differ in flight metrics or post‐flight metabolic rates. The results suggest that flight in eastern North American and Puerto Rican monarchs is similar during the breeding season, yet the milkweed the caterpillars consume has important implications for flight performance.

Merchlinsky, Alex; Frankson, Paul T.; Gitzen, Robert; Lepczyk, Christopher A.; Mohan, Jacqueline E.; Warren, Robert J.

doi: 10.1111/een.13256pmid: N/A

1. Non‐native species may be the cause of native species declines or an effect of habitat degradations that promote the former and damage the latter. Social insects are extraordinarily successful organisms, and non‐native social insects, such as ants, often are very successful invaders of novel habitats.

Bosch, Michael J.; Ives, Anthony R.

doi: 10.1111/een.13257pmid: N/A

Many species of insects show phenotypically plastic dispersal traits in response to suboptimal environmental conditions. These polyphenetic traits can have large impacts on the population dynamics of the dispersing insects. Therefore, it is important to understand what environmental factors affect the development of dispersal traits and how these factors affect population dynamics via immigration/emigration. Pea aphids (Acyrthosiphon pisum) exhibit a polyphenetic wing dimorphism in which individuals are either winged (alate) or not (apterous). The production of alate offspring is determined by environmental cues experienced by the mother. Environmental factors associated with these cues have been intensively studied, with crowding, host plant quality, natural enemies, fungal infection, and viral infection being shown to affect the production of pea aphid alates under controlled laboratory conditions. Nonetheless, environmental factors affecting alate production have rarely been studied in field populations of pea aphids. Using data from a three‐year study of alate production in 5–9 alfalfa (lucerne) fields, we examined the effects of (i) pea aphid abundance, (ii) host plant maturity, (iii) temperature, (iv) predator and herbivore abundance, (v) parasitism, and (vi) entomopathic fungal incidence. In twice‐weekly samples taken over the growing season, alate production ranged from 0% to 83% of the nymphal population. Pea aphid abundance, temperature, and alfalfa maturity together explained 67% of the variation in alate production. The other factors we investigated explained little variation. These results suggest there is a limited number of key environmental factors that consistently predict changes in alate production in field populations, while many factors identified in lab studies may be unimportant. Our results highlight the value of investigating factors affecting the expression of plastic traits in insect species at a broad spatiotemporal scale and under natural conditions.

Vargas‐Cardoso, Orthon Ricardo; Toledo‐Hernández, Víctor Hugo; Corona‐López, Angélica M.; Flores‐Palacios, Alejandro; Figueroa‐Brito, Rodolfo; Sosa‐Armenta, Jessica Maria; López‐Martínez, Víctor

doi: 10.1111/een.13259pmid: N/A

1. There is little information on tropical dry forests regarding cerambycids and their relationship with seasonality, vertical stratification, and physical characteristics of the wood they require to develop.