Understanding predator–prey interactions is essential for successful pest management by using predators, especially for the suppression of novel invasive pest. The green lacewing Chrysopa formosa is a promising polyphagous predator that is widely used in the biocontrol of various pests in China, but information on the control efficiency of this predator against the seriously invasive pest Spodoptera frugiperda and native Spodoptera litura is limited. Here we evaluated the predation efficiency of C. formosa adults on eggs and first- to third-instar larvae of S. frugiperda and S. litura through functional response experiments and determined the consumption capacity and prey preference of this chrysopid. Adults of C. formosa had a high consumption of eggs and earlier instar larvae of both prey species, and displayed a type II functional response on all prey stages. Attack rates of the chrysopid on different prey stages were statistically similar, but the handling time increased notably as the prey developed. The highest predation efficiency and shortest-handling time were observed for C. formosa feeding on Spodoptera eggs, followed by the first-instar larvae. C. formosa exhibited a significant preference for S. litura over S. frugiperda in a two-prey system. In addition, we summarized the functional response and predation efficiency of several chrysopids against noctuid pests and made a comparison with the results obtained from C. formosa. These results indicate that C. formosa has potential as an agent for biological control of noctuid pests, particularly for the newly invasive pest S. frugiperda in China.

Encounter rates of carnivores with prey are dependent on spatial and temporal overlap, and are often highest with their preferred prey. The Critically Endangered Sumatran tiger Panthera tigris sumatrae is dependent on prey populations, but little is known about its prey preferences. We collected camera-trap data for 7 years (2010–2016) in Bukit Barisan Selatan National Park, Sumatra, to investigate spatial and temporal overlap of tigers with potential prey species. We also developed a novel method to predict predator–prey encounter rates and potential prey preferences from camera-trap data. We documented at least 10 individual tigers, with an overall detection rate of 0.24 detections/100 trap nights. Tigers exhibited a diurnal activity pattern and had highest temporal overlap with wild boar Sus scrofa and pig-tailed macaques Macaca nemestrina, but highest spatial overlap with wild boar and sambar deer Rusa unicolor. We created a spatial and temporal composite score and three additional composite scores with adjustments for the spatial overlap and preferred prey mass. Wild boars ranked highest for all composite scores, followed by sambar deer, and both are known as preferred tiger prey in other areas. Spatial and temporal overlaps are often considered as separate indices, but a composite score may facilitate better predictions of encounter rates and potential prey preferences. Our findings suggest that prey management efforts in this area should focus on wild boar and sambar deer, to ensure a robust prey base for this Critically Endangered tiger population.

Difficult terrain and inclement weather limit our knowledge of large predators, such as the tiger Panthera tigris, in the Himalayas. A lack of empirical data on large carnivores can lead to mismanagement of protected areas and population declines. We used non-invasive genetic and remote sensing data to inform the management of such high-altitude protected areas. We used the tiger as a focal species to investigate prey preference and habitat suitability in India's Buxa Tiger Reserve, which encompasses several eco-geographical regions in the Himalayan and subtropical zones. During 2010–2013, 909 faecal samples were collected, of which 372 were confirmed, using genetic analysis, to be of tiger origin. Fourteen prey species/groups were identified in 240 tiger faecal samples, largely dominated by goats Capra spp. (26.59%), rhesus macaques Macaca mulatta (22.22%) and cattle Bos spp. (20.63%). Considering only the wild prey species for which survey data are available, however, and frequency of occurrence of prey in faecal samples, hog deer Axis porcinus, sambar deer Rusa unicolor and spotted deer Axis axis were the most preferred prey species. Using faecal sample locations to examine the relationship between tiger presence and environmental features indicated that the niche for tigers is narrower than the available protected area: c. 62% of core protected area is suitable, of which only 17% is highly suitable for tigers. Tigers prefer dense vegetation, open forests, riverine vegetation and areas close to water sources. Faecal sample-based studies have the potential to generate data that can help us understand the ecology of elusive carnivore species inhabiting high-altitude landscapes.

The relationships between the predatory mites, Amblyseius swirskii (Athias-Henriot) and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), and their prey, western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae), were investigated to determine the effects of predation on intra-guild or extra-guild prey and predator preference. Life history characteristics of both predatory mites were measured when fed eggs and larvae of the other predator species and compared to data obtained when the predators were fed thrips larvae. In addition, choice tests were conducted to determine if the predators had a preference for different prey or if they were indiscriminate predators. Amblyseius swirskii appears to be an important intra-guild predator of N. cucumeris juveniles because of a high predation rate and a preference for N. cucumeris juveniles over thrips. Neoseiulus cucumeris is also an intra-guild predator of A. swirskii juveniles; however, it has a lower predation rate than A. swirskii. Contrary to intra-guild predation theory, intra-guild prey was an equally good or better food source than thrips (extra-guild prey) for both predators, based on high oviposition rates and fast development times. The results of this study indicate a high potential for negative interactions between A. swirskii and N. cucumeris when used together in biological control of thrips.

The egg capsules and larvae of Engina armillata (Reeve) (Gastropoda: Buccinidae) are described for the first time. Its general ecology in the Cape d'Aguilar Marine Reserve, Hong Kong, is also described, the species occurring under stable boulders with a community of encrusting species, notably sedentary tubicolous polychaetes. The diet of E. armillata at Cape d'Aguilar consists of serpulid and spirobid polychaetes. Of the four commonest such species, Hydroides elegans was preferred to Pomatoleios kraussi, Simplicaria pseudomilitaris and Spirorbis foraminosus. Consumption rates by E. armillata varied considerably amongst individuals, but generally ranged between 1.2 and 6.5% of predator dry weight day-1 during conditions wherein prey quantity was maintained. Such a figure is low when compared to other boring naticid and muricid predatory gastropods which spend much time and energy accessing their prey. The ready availability of easily accessible prey may account for the low consumption rate of E. armillata (as also seen in other non-boring predatory gastropods) and explain its apparent specialist feeding habits.