Efficacy of visual encounter surveys for coastal tailed frog detection

Coastal tailed frogs Ascaphus truei inhabit montane streams and forested habitats in the Coast and Cascade Mountains from northern California, USA, to the Skeena River watershed in northwestern British Columbia (BC), Canada. Terrestrial adults and juveniles of this cryptic biphasic species are difficult to survey as they are small, do not vocalize, and may be associated with woody ground structures or subsurface refugia at considerable distances from natal streams. We performed a comparative analysis of the detection rate of post-metamorphic coastal tailed frogs and ecological factors hypothesized to influence detection when conducting visual encounter and pitfall trap surveys. We conducted concurrent surveys in northwestern BC at six sites over similar time periods using both techniques. The average detection rate of visual encounter surveys ( = 0.249, SD = 0.702) was greater than that of pitfall sampling ( = 0.138, SD = 0.773) when cool temperatures and high humidity favor above-ground movement during the daytime. Light-touch ground searches of refuge habitats likely enhanced detection during visual surveys. Although the average detection rate was less, pitfall traps provided 24-hour sampling and were less affected by the experience of the surveyor and the occurrence of ground cover. In general, variation in seasonal behavior influenced detection regardless of method. The relatively higher cost and fixed nature of pitfall traps should be weighed against the ability to apply more cost-effective visual encounter surveys to a greater number of sites.

Effects of calcium cyanamide on Collembola in a standardized field test: Part 1. Rationale and performance of the study

Background A field study lasting one year was performed to study the effects of a calcium cyanamide fertiliser (trade name: Perlka®) on Collembola in order to support the terrestrial risk assessment under the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation. Due to the lack of an appropriate guidance document, the design of the study was based on the ISO Guideline 11268–3, originally developed for earthworm field studies. However, the sampling procedure was adapted accordingly by applying ISO Guideline 23611–2, i.e. taking soil core and pitfall trap samples. Two groups of four plots each were treated with 200 kg/ha and 400 kg/ha Perlka®, respectively. A third group served as a fertiliser control, i.e. it was treated with a standard urea fertiliser (172.9 kg Piagran®/ha) at the same total nitrogen rate (79.5 kg/ha) as provided by the high Perlka® application rate. The fourth group served as negative control without any fertiliser treatment and the fifth group was treated with the reference item Agriclor® (480 g a.i./L chlorpyrifos), known to be toxic to springtails. Results In total 16 different Collembola species were determined. For seven species, covering all life form types, a reliable statistical evaluation was possible, which was reflected in correspondingly low MDD values in the study. A statistically significant decrease of the abundance (at least 50%) on the reference item plots compared to the untreated control was observed for six species, thus demonstrating the sensitivity of the Collembola community. Conclusion No long-lasting effects of the Perlka® application rates could be observed for any of the Collembola species. In order to support risk assessors in both industry and authorities in the interpretation of large and complex data sets typical for field studies with chemicals, further guidance on implementation and data interpretation is urgently needed.

Pemantauan Keanekaragaman Hama dan Musuh Alami Tanaman Ubi Jalar dengan Pitfall Trap

The abundance of pest and natural enemy populations on a land can be given in the diversity and abundance of feeding sources and other available resources. The purpose of this study was to determine the diversity of pests and natural enemies of sweet potato plants. Research on land with three types of sweet potatoes, namely yellow sweet potatoes with narrow leaves, yellow sweet potatoes with broad leaves, and sweet potatoes with white leaves. Around the research area are long beans, papaya, guava, soursop, and durian. Sampling of pests and natural enemies by using a pitfall trap. The data analyzed was in the form of the Shannon-Weaver (H') diversity index. The index of pest diversity of the order Coleoptera on narrow-leaved yellow sweet potato, broad-leaved yellow sweet potato, and white sweet potato was 0,160; 0,1270; and 0,1300. The index of pest diversity of the order Orthoptera on narrow-leaved yellow sweet potato, broad-leaved yellow sweet potato, and white sweet potato was 0,3585; 0,3599; and 0,3632. The index of pest diversity of the order Hemiptera on narrow-leaved yellow sweet potato, broad-leaved yellow sweet potato, and white sweet potato was 0,0635; 0,0771; and 0,1300. Diversity index of natural enemies of the order Araneae on narrow-leaved yellow sweet potato, broad-leaved yellow sweet potato, and white sweet potato 0.2180; 0.3061; and 0.2705. The three sweet potato fields had a low diversity index.

KERAGAMAN JENIS SERANGGA DIURNAL DI KAWASAN KAMPUS UNIVERSITAS MUHAMMADIYAH ACEH SEBAGAI MEDIA PEMBEJARAN ZOOLOGI INVERTEBRATA

Penelitian ini dilaksanakan di kawasan kampus Universitas Muhammadiyah Aceh pada bulan Mei sampai Agustus 2015 yang bertujuan untuk mengetahui jenis serangga diurnal, tingkat keragaman dan menjadikan jenis serangga diurnal sebagai media pembelajaran zoologi invertebrata. Pengambilan sampel penelitian dilakukan dengan menggunakan insect net, pitfall trap, areal bait trap, dan aspirator pada tiga stasiun pengamatan yang telah ditentukan. Analisis data dilakukan dengan cara mendeskripsikan setiap jenis serangga diurnal yang ditemukan. Selanjutnya untuk mengetahui tingkat keragaman jenis serangga diurnal di kampus Universitas Muhammadiyah Aceh digunakan indeks keragaman Shannon Wiener (H’). Hasil penelitian di peroleh serangga diurnal sebanyak 1580 individu yang terdiri dari 8 ordo, 17 familia dengan 26 jenis. 26 jenis serangga diurnal masing – masing terdiri masing - masing 7 jenis dari ordo Hymenoptera famili Formicidae, Apidae, dan Perilampidae, 4 jenis ordo Hemiptera famili Lygaeidae, Alydidae, Coreidae dan Pentatomidae, 2 jenis dari ordo Diptera famili Calliphoridae dan Muscidae, 2 jenis dari ordo Coleoptera famili Coccinellidae, 4 jenis dari ordo Lepidoptera famili Nymphalidae dan Pieridae , 3 ordo jenis dari Orthoptera famili Acrididae dan Tetrigidae, 1 jenis dari ordo Mantodea famili Mantodidae dan 3 jenis dari ordo Odonata famili Libellulidae dan Coenagrionidae. Hasil analisis indeks keragaman menunjukkan nilai 1,68 yang berarti tingkat keragaman serangga diurnal di kawasan kampus Universitas Muhammadiyah Aceh tergolong sedang, dengan indeks kemerataan 0,51 artinya bahwa distribusi jumlah individu setiap jenis serangga diurnal di masing - masing stasiun penelitian relatif terdistribusi secara merata

Intercropping With Peppermint Increases Ground Dwelling Insect and Pollinator Abundance and Decreases Drosophila suzukii in Fruit

Intercropping can be used to reduce pest insects within agricultural systems, e.g., through deterring pests directly or by increasing habitat for their natural enemies. For example, plant produced volatile organic compounds (VOCs) can deter or confuse host-finding by insects through olfactory disruption. Drosophila suzukii is an invasive fruit fly of agricultural concern as it can lay its eggs in both ripening and fresh fruits and, uses olfactory cues to identify its wide range of host plants. Peppermint plants (Mentha × piperita) produce high levels of VOCs while growing and may, therefore, be suitable as an intercrop to reduce D. suzukii infestations in the field, as peppermint essential oil VOCs have previously been shown to deter D. suzukii in olfactory trials. We conducted a field intercropping experiment to evaluate the effectiveness of peppermint plants compared to traditional ryegrass/clover mixes in reducing D. suzukii oviposition in the field, and the effect of peppermint intercrops on other invertebrates. In the field, we monitored sentinel fruit baits weekly for D. suzukii infestation. Additionally, we monitored intercropping effects on the invertebrate community through weekly pitfall trap collection and through a pollinator point survey. We monitored for local, farm level presence of D. suzukii through apple cider vinegar traps within crop fields and along hedgerows and found high abundance of D. suzukii (>3,000 individuals trapped). Peppermint intercrops had fewer D. suzukii emerge from fruit baits and supported greater beneficial insect abundance (predators and pollinators) compared to ryegrass/clover. However, levels of D. suzukii were low across both intercrop types. Overall, we found that peppermint intercrops could be a potential aromatic intercrop used to reduce D. suzukii adult emergence from fruit compared to conventional ryegrass/clover mixes, however this trial should be replicated over multiple growing seasons, geographic locations, and host fruits. Furthermore, further study should determine the effects of the intercrop on the focal crop of interest.

Comparison of the efficiency and ethical implications of pitfall and Tomahawk traps on Virginia opposums (Didelphis virginiana)

The choice of methods for trapping animals can greatly affect the studies and their results, despite that there are relatively few studies on the matter. Thus, the purpose of this study is to compare two common methods of live trapping (Tomahawk traps and pitfall traps), their efficiency and ethical implications for trapping Virginia opossums (Didelphis virginiana). Traps were located in a paired design, the trapped animals were checked for sex, injuries caused by the trap and stress level, then marked and released in the same spot. At the same time, costs of both trap types were compared. Tomahawk traps were 60 % more efficient to trap opossums but the pitfall traps had better results in all the other categories: were more cost-effective, did not injure the animals as often and were less stressful. Neither type of trap presented bias in sex proportion or number of recaptured animals. In general, both types of traps resulted to be effective, the pitfall trap was the better option in almost all of the categories but has the disadvantage that in the infrequent event of two males being caught on in the same trap, they are likely to fight.

Batch extraction of morphological and color metrics from invertebrate samples. v1

This protocol is the complete methods used to extract abundance, morphology and color data from samples of invertebrates. We developed this protocol specifically to measure invertebrate by-catch from pitfall traps collected by the National Ecological Observatory Network (NEON), but these methods could be extended to any invertebrate samples. These methods were used in the publications: Blair, J.,M.D. Weiser, M. Kaspari, M.J. Miller, C. Siler and K. Marshall. 2020. Robust and simplified machine learning identification of pitfall trap-collected ground beetles at the continental scale. Ecology and Evolution 10(23): 13143-13153. DOI:10.1002/ece3.6905. Weiser, M.D., K.E. Marshall, M.J. Miller, C.D. Siler, S.N. Smith & M. Kaspari. in review at Oikos (October 2021). Robust metagenomic evidence that local assemblage richness increases with latitude in ground-active invertebrates of North America.

KEANEKARAGAMAN JENIS SEMUT (HYMENOPTERA: FORMICIDAE) PADA EKOSISTEM TANAMAN TEBU PHT DAN KONVENSIONAL

Pada budidaya tanaman tebu (Saccharum officinarium L.) seringkali terjadi hambatan sehingga dapat menurunkan hasil produksi, salah satunya ialah serangan hama. Semut (Hymenoptera: Formicidae) merupakan serangga musuh alami yang berperan sebagai predator. Tujuan dari penelitian ini yaitu untuk mengetahui jenis – jenis semut, peran, dan pengaruh perbedaan yang terdapat di ekosistem tanaman tebu PHT dan konvensional. Kegiatan penelitian ini dilaksanakan pada bulan Agustus – Oktober 2020. Tempat kegiatan pelaksanaan penelitian yaitu di Balai Penelitian Tanaman Pemanis dan Serat, Karangploso, Malang. Penelitian ini bersifat deskriptif kuantitatif dengan menggunakan metode Pitfall trap dan umpan tuna. Berdasarkan hasil penelitian semut yang ditemukan pada lahan pengamatan terdiri dari 4 subfamili dan 9 genus semut. Jumlah keseluruhan genus semut yang di dapat pada lahan PHT yaitu 1506 individu dan pada lahan Konvensional 1240 individu. Keanekaragaman pada lahan pengamatan dalam keadaan yang stabil dengan keanekaragaman dalam kategori sedang. Tingkat penyebaran jenis hampir merata. Kekayaan spesies pada kedua lahan rendah serta tidak ada spesies yang mendominasi pada lahan PHT dan konvensional. Peran semut yang ditemukan pada lahan pengamatan yaitu sebagai predator dan sebagai pencari makan (foragers).

Mating marks on museum specimens reveal breeding patterns in species of Pterostichus Bonelli (Carabidae, Pterostichini)

We found distinct and consistently placed, species- and sex-specific abrasions of the cuticle on museum specimens of 14 species of the Pterostichus Bonelli, 1810 (Carabidae, Pterostichini) subgenus Hypherpes Chaudoir, 1838. We deduced that these marks are generated during mating and, therefore, can be used to distinguish between preserved specimens of beetles that had previously mated at the time of capture and those that had not mated. In addition to describing and detailing the occurrence of the marks and providing evidence that they are the result of mating, we demonstrate their utility for inferring life history using a museum voucher collection. By scoring these indications of mating from pinned specimens, we describe life cycle patterns in two similar, relatively closely related and sympatric species of the subgenus Hypherpes, P. vicinus Mannerheim, 1843 and P. californicus (Dejean, 1828). Both were sampled during a pitfall trap study in Contra Costa, California, USA from 2014–2019 and deposited in the Essig Museum of Entomology, UC Berkeley. Both species had very low adult activity through the drought and end of drought period prior to the spring of 2017 and are significantly more abundant in the post-drought period. Based on mating marks, both species responded to accumulated precipitation ending the drought by the emergence of an active, mostly unmated cohort of adults. The spring activity peak, following the end of the drought, was dominated by unmarked and presumably unmated beetles, but samples from subsequent springs included a nearly equal mix of beetles showing mating marks and apparently unmated beetles. The beetle activity appears to correspond more with the accumulated rainfall of the preceding rainy season than with the rains of the sample year. Beetles sampled in autumn and winter (rainy season) predominantly show mating marks. The occurrence throughout the year of beetles that are marked as having mated is consistent with iteroparous beetles with a lifespan of more than one year and also consistent with dynamic phenotypic polyvariance in which the adult activity period is synchronised by adjusting development time. The dominant pattern fits with a life cycle that is typically annual univoltine, or possibly biennial semivoltine in dry years, rainy season breeding (autumn-winter) iteroparous, with adult summer aestivation and possibly facultative larval hibernation. However, unmarked and so apparently unmated individuals and teneral adults were captured during peak activity periods regardless of the season, suggesting that either the beetles diapause as teneral adults that then complete development and become active at various points during the year and/or there are multiple periods of breeding and oviposition each year in at least some portion of the population.

Sand-throwing behaviour in pit-building antlion larvae: insights from finite-element modelling

Sandy pitfall traps of antlions are elaborate constructions to capture prey. Antlions exploit the interactions between the particles in their habitat and build a stable trap. This trap is close to the unstable state; prey items will slide towards the centre—where the antlion ambushes—when entering the trap. This is efficient but requires permanent maintenance. According to the present knowledge, antlions throw sand, mainly to cause sandslides towards the centre of the pit. We hypothesized that: (i) sand-throwing causes sandslides towards the centre of the pit and (ii) sand-throwing constantly maintains the pitfall trap and thus keeps its efficiency high. Using laboratory experiments, as well as finite-element analysis, we tested these hypotheses. We show, experimentally and numerically, that sand that accumulates at the centre of the pit will be removed continuously by sand-throwing, this maintenance is leading to slope condition close to an unstable state. This keeps the slope angle steep and the efficiency of the trap constant. Furthermore, the resulting sandslides can relocate the trapped prey towards the centre of the pit. This study adds further insights from specific mechanical properties of a granular medium into the behavioural context of hunting antlion larvae.