Impacts of nitrogen fertilizer on major insect pests and their predators in transgenic Bt rice lines T2A‐1 and T1C‐19

Nitrogen is a critical factor for plant development and nitrogen input is one of the important tactics to enhance the development and yield of crops. Nevertheless, nitrogen input could influence the occurrence of insects positively or negatively. Nitrogen is also one of the main elements composing the insecticidal crystal (Cry) protein. Cry protein production could affect nitrogen partitioning in Bt plants and as such nitrogen input may influence insect pest management in transgenic Bt rice, Oryza sativa L. (Poaceae). To test this possibility, we evaluated the impacts of nitrogen regimes on the main insect pests and their predators on two Bt rice lines, T2A‐1 and T1C‐19, expressing Cry2A and Cry1C, respectively, and their non‐transgenic parental counterpart MH63. The results showed that Cry proteins with different nitrogen regimes have enough insecticidal activity on rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Crambidae), in both laboratory and field experiments. Laboratory studies indicated that relevant parameters of ecological fitness in brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), a non‐target insect pest, were significantly affected by nitrogen input both on Bt and MH63 rice lines. Nymphal survival, female adult longevity, and egg hatchability in N. lugens differed significantly among rice varieties. The experiments conducted in rice fields also demonstrated that nitrogen was positively correlated with the abundance of N. lugens on Bt rice, similar to that on MH63 rice. The abundances of two predators – the wolf spider Pirata subpiraticus (Boesenberg & Strand) (Araneae: Lycosidae) and the bug Cyrthorhinus lividipennis Reuter (Hemiptera: Miridae) – were significantly affected by rice growth stages but not by nitrogen input and rice varieties. In conclusion, the above results indicate that high nitrogen regimes for Bt rice (T2A‐1 and T1C‐19) and non‐Bt rice (MH63) cannot facilitate the management of insect pests.     

Host plant preference and offspring performance of a leaf‐mining moth,Caloptilia fraxinella,on two Fraxinus species

The preference‐performance or ‘mother‐knows‐best’ hypothesis states that female insects choose to oviposit on a host plant that increases the performance of their offspring. This positive link between host plant choice and larval performance is especially important for leaf miners with non‐motile larvae that are entirely dependent upon the oviposition choice of the female for host plant location. Preference and performance of the ash leaf coneroller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillariidae), a specialist on ash trees, Fraxinus spp. (Oleaceae), were tested in a series of laboratory and field experiments. Female C. fraxinella were exposed to two closely related hosts, black ash, Fraxinus nigra Marshall, and green ash, Fraxinus pennsylvanica Marshall var. subintegerrima (Vahl), in oviposition choice and wind tunnel flight experiments to determine which host is most attractive for oviposition. Caloptilia fraxinella females were inconsistent in host choice, yet performance of larvae was greater on green than black ash. In preference studies, C. fraxinella preferred to oviposit on black ash when leaflets were removed from the tree, but preferred intact green ash over black ash seedlings for oviposition and host location in a wind tunnel. In the field, however, more C. fraxinella visited black ash var. ‘Fallgold’ at leaf flush than green ash at the same sites. Age of the ash leaflet also influences oviposition in this leaf miner and females preferred new over old leaflets for oviposition. Performance of C. fraxinella larvae was evaluated in field and laboratory experiments and was greater on green ash than on black ash in both experiments based on larval survival and development time parameters. The stronger oviposition and host location preference in the field for black ash were not linked to enhanced performance of offspring, as green ash was the superior host, supporting higher larval survival and faster development. A stronger host location preference in the wind tunnel for green ash over black ash, however, suggests that under certain circumstances with this moth species, ‘mother (may) know best’.     

Drosophila rely on learning while foraging under semi‐natural conditions

Learning is predicted to affect manifold ecological and evolutionary processes, but the extent to which animals rely on learning in nature remains poorly known, especially for short‐lived non‐social invertebrates. This is in particular the case for Drosophila, a favourite laboratory system to study molecular mechanisms of learning. Here we tested whether Drosophila melanogaster use learned information to choose food while free‐flying in a large greenhouse emulating the natural environment. In a series of experiments flies were first given an opportunity to learn which of two food odours was associated with good versus unpalatable taste; subsequently, their preference for the two odours was assessed with olfactory traps set up in the greenhouse. Flies that had experienced palatable apple‐flavoured food and unpalatable orange‐flavoured food were more likely to be attracted to the odour of apple than flies with the opposite experience. This was true both when the flies first learned in the laboratory and were then released and recaptured in the greenhouse, and when the learning occurred under free‐flying conditions in the greenhouse. Furthermore, flies retained the memory of their experience while exploring the greenhouse overnight in the absence of focal odours, pointing to the involvement of consolidated memory. These results support the notion that even small, short lived insects which are not central‐place foragers make use of learned cues in their natural environments.     

The genetics of a putative social trait in natural populations of yeast

The sharing of secreted invertase by yeast cells is a well‐established laboratory model for cooperation, but the only evidence that such cooperation occurs in nature is that the SUC loci, which encode invertase, vary in number and functionality. Genotypes that do not produce invertase can act as ‘cheats’ in laboratory experiments, growing on the glucose that is released when invertase producers, or ‘cooperators’, digest sucrose. However, genetic variation for invertase production might instead be explained by adaptation of different populations to different local availabilities of sucrose, the substrate for invertase. Here we find that 110 wild yeast strains isolated from natural habitats, and all contained a single SUC locus and produced invertase; none were ‘cheats’. The only genetic variants we found were three strains isolated instead from sucrose‐rich nectar, which produced higher levels of invertase from three additional SUC loci at their subtelomeres. We argue that the pattern of SUC gene variation is better explained by local adaptation than by social conflict.     

Host specificity of two pollinating seed‐consuming fly species is not related to soil moisture of host plant in the high Himalayas

Studying the drivers of host specificity can contribute to our understanding of the origin and evolution of obligate pollination mutualisms. The preference–performance hypothesis predicts that host plant choice of female insects is related mainly to the performance of their offspring. Soil moisture is thought to be particularly important for the survival of larvae and pupae that inhabit soil. In the high Himalayas, Rheum nobile and R. alexandrae differ in their distribution in terms of soil moisture; that is, R. nobile typically occurs in scree with well‐drained soils, R. alexandrae in wetlands. The two plant species are pollinated by their respective mutualistic seed‐consuming flies, Bradysia sp1. and Bradysia sp2. We investigated whether soil moisture is important for regulating host specificity by comparing pupation and adult emergence of the two fly species using field and laboratory experiments. Laboratory experiments revealed soil moisture did have significant effects on larval and pupal performances in both fly species, but the two fly species had similar optimal soil moisture requirements for pupation and adult emergence. Moreover, a field reciprocal transfer experiment showed that there was no significant difference in adult emergence for both fly species between their native and non‐native habitats. Nevertheless, Bradysia sp1., associated with R. nobile, was more tolerant to drought stress, while Bradysia sp2., associated with R. alexandrae, was more tolerant to flooding stress. These results indicate that soil moisture is unlikely to play a determining role in regulating host specificity of the two fly species. However, their pupation and adult emergence in response to extremely wet or dry soils are habitat‐specific.     

The distribution of the orange‐striped green anemone,Diadumene lineata,in relation to environmental factors along coastal British Columbia,Canada

The cosmopolitan nonindigenous sea anemone, Diadumene lineata, has been recorded from the Pacific coast of Canada since 1859. Despite its long historical presence in the region, the factors influencing the distribution of this species in British Columbia, Canada, are poorly understood, as are the factors that may restrict its local abundance. We conducted large‐scale surveys of D. lineata during the winter and summer of 2016, coupled with higher frequency surveys at one focal site. Furthermore, we used laboratory and field experiments to determine the potential importance of a large‐scale driver, salinity, and a small‐scale driver, microhabitat within boulders, in setting distributional limits at various spatial scales. Our results confirm that D. lineata is widely distributed within the Salish Sea. This broad distribution may be facilitated by post‐introduction dispersal; we observed anemones attached to floating substrata, and a few mature specimens contained eggs, suggesting that reproduction is perhaps not limited to asexual fission. We found that D. lineata was abundant throughout the year, although absent from the lowest salinity sites. This corresponded with our laboratory experiments, in which survival of individuals of D. lineata declined at salinities below 10 psu, and no survivors were observed at or below 2 psu. Manipulative experiments in the field demonstrated that survival was high under rocks where D. lineata is commonly found, but was reduced on the tops of rocks, highlighting the importance of microhabitat refugia in buffering temperature and reducing desiccation. A better understanding of the factors that limit the broad‐scale and local distribution of this anemone are an important step in determining potential ecological impacts of this organism and how distributions may shift into the future.     

An elusive endosymbiont: Does Wolbachia occur naturally in Aedes aegypti?

Wolbachia are maternally inherited endosymbiotic bacteria found within many insect species. Aedes mosquitoes experimentally infected with Wolbachia are being released into the field for Aedes‐borne disease control. These Wolbachia infections induce cytoplasmic incompatibility which is used to suppress populations through incompatible matings or replace populations through the reproductive advantage provided by this mechanism. However, the presence of naturally occurring Wolbachia in target populations could interfere with both population replacement and suppression programs depending on the compatibility patterns between strains. Aedes aegypti were thought to not harbor Wolbachia naturally but several recent studies have detected Wolbachia in natural populations of this mosquito. We therefore review the evidence for natural Wolbachia infections in A. aegypti to date and discuss limitations of these studies. We draw on research from other mosquito species to outline the potential implications of natural Wolbachia infections in A. aegypti for disease control. To validate previous reports, we obtained a laboratory population of A. aegypti from New Mexico, USA, that harbors a natural Wolbachia infection, and we conducted field surveys in Kuala Lumpur, Malaysia, where a natural Wolbachia infection has also been reported. However, we were unable to detect Wolbachia in both the laboratory and field populations. Because the presence of naturally occurring Wolbachia in A. aegypti could have profound implications for Wolbachia‐based disease control programs, it is important to continue to accurately assess the Wolbachia status of target Aedes populations.     

Neuronal‐specific proteasome augmentation via Prosβ5 overexpression extends lifespan and reduces age‐related cognitive decline

Cognitive function declines with age throughout the animal kingdom, and increasing evidence shows that disruption of the proteasome system contributes to this deterioration. The proteasome has important roles in multiple aspects of the nervous system, including synapse function and plasticity, as well as preventing cell death and senescence. Previous studies have shown neuronal proteasome depletion and inhibition can result in neurodegeneration and cognitive deficits, but it is unclear if this pathway is a driver of neurodegeneration and cognitive decline in aging. We report that overexpression of the proteasome β5 subunit enhances proteasome assembly and function. Significantly, we go on to show that neuronal‐specific proteasome augmentation slows age‐related declines in measures of learning, memory, and circadian rhythmicity. Surprisingly, neuronal‐specific augmentation of proteasome function also produces a robust increase of lifespan in Drosophila melanogaster. Our findings appear specific to the nervous system; ubiquitous proteasome overexpression increases oxidative stress resistance but does not impact lifespan and is detrimental to some healthspan measures. These findings demonstrate a key role of the proteasome system in brain aging.     

A genome‐wide significant association on chromosome 2 for footrot resistance/susceptibility in Swiss White Alpine sheep

Footrot is one of the most important causes of lameness in global sheep populations and is characterized by a bacterial infection of the interdigital skin. As a multifactorial disease, its clinical representation depends not only on pathogen factors and environmental components but also on the individual resistance/susceptibility of the host. A genetic component has been shown in previous studies; however, so far no causative genetic variant influencing the risk of developing footrot has been identified. In this study, we genotyped 373 Swiss White Alpine sheep, using the ovine high‐density 600k SNP chip, in order to run a DNA‐based comparison of individuals with known clinical footrot status. We performed a case–control genome‐wide association study, which revealed a genome‐wide significant association for SNP rs418747104 on ovine chromosome 2 at 81.2 Mb. The three best associated SNP markers were located at the MPDZ gene, which codes for the multiple PDZ domain crumbs cell polarity complex component protein, also known as multi‐PDZ domain protein 1 (MUPP1). This protein is possibly involved in maintaining the barrier function and integrity of tight junctions. Therefore, we speculate that individuals carrying MPDZ variants may differ in their footrot resistance/susceptibility due to modified horn and interdigital skin integrity. In conclusion, our study reveals that MPDZ might represent a functional candidate gene, and further research is needed to explore its role in footrot affected sheep.     

Innovation in teaching and learning invertebrate zoology in remote and online classrooms

The COVID‐19 global pandemic caused instructors to pivot to remote and online teaching, an especially challenging task in hands‐on classes such as invertebrate biology. In this special 25th anniversary issue of Invertebrate Biology, the authors present a variety of clever and effective ways to help invertebrate biology instructors adapt to teaching in an online environment. Student‐centered research and learning are essential in all biology classes, and we explore scientific writing, field trips, do‐it‐yourself laboratories, and more. These techniques will be useful for classes of varying sizes and types, from non‐major undergraduates to graduate students, even after the pandemic is over. Innovation for teaching invertebrate biology online may help facilitate more inclusive courses that serve diverse students more equitably. Ideas for how to best move traditionally hands‐on laboratories into online or remote formats are currently also being informally discussed in a collaborative online space for instructors.     

生物学教学中研究型教学方法与内容的探索

培养创新性人才是中国高校的教学目的之一, 实现这一目的需要改革传统的教学方法。为此, 许多学者引入了西方的研究型教学理念, 并讨论了这种教学理念对新时代教学改革的意义, 但仍然停留在理论探讨的层面上, 几乎没有提出对课堂教学有实用价值的研究型教学方法和具体内容。笔者根据自己多年的遗传学教学实践和经验, 结合目前大学教学普遍采用的教师主导型授课模式, 提出了适合生物学课堂教学的、比较全面而具体的研究型教学内容和评估方法, 认为研究型教学法至少应包含7个方面的措施：(1) 讲述科研历史, 学习提出科学问题的技巧; (2) 重演实验过程, 学习解决科学问题的研究技巧; (3) 分析实验结果, 学习从结果推出科学结论; (4) 设计虚拟实验, 学习立项组织科研; (5)侦探断案式的讲课方式, 学习科学探秘的逻辑; (6) 引导学生阅读, 学习查阅文献与梳理和总结研究进展的能力; (7) 因材施教, 提前单独培养优秀本科生。此外本文还讨论了在课程考试中如何考察研究型教学的效果。     

Facultative pupal mating in Heliconius erato: Implications for mate choice,female preference,and speciation

Mating systems have broad impacts on how sexual selection and mate choice operate within a species, but studies of mating behavior in the laboratory may not reflect how these processes occur in the wild. Here, we examined the mating behavior of the neotropical butterfly Heliconius erato in the field by releasing larvae and virgin females and observing how they mated. H. erato is considered a pupal‐mating species (i.e., males mate with females as they emerge from the pupal case). However, we observed only two teneral mating events, and experimentally released virgins were almost all mated upon recapture. Our study confirms the presence of some pupal‐mating behavior in H. erato, but suggests that adult mating is likely the prevalent mating strategy in this species. These findings have important implications for the role of color pattern and female mate choice in the generation of reproductive isolation in this diverse genus.     

Stressful environments can indirectly select for increased longevity

Longevity is modulated by a range of conserved genes in eukaryotes, but it is unclear how variation in these genes contributes to the evolution of longevity in nature. Mutations that increase life span in model organisms typically induce trade‐offs which lead to a net reduction in fitness, suggesting that such mutations are unlikely to become established in natural populations. However, the fitness consequences of manipulating longevity have rarely been assessed in heterogeneous environments, in which stressful conditions are encountered. Using laboratory selection experiments, we demonstrate that long‐lived, stress‐resistant Caenorhabditis elegans age‐1(hx546) mutants have higher fitness than the wild‐type genotype if mixed genotype populations are periodically exposed to high temperatures when food is not limited. We further establish, using stochastic population projection models, that the age‐1(hx546) mutant allele can confer a selective advantage if temperature stress is encountered when food availability also varies over time. Our results indicate that heterogeneity in environmental stress may lead to altered allele frequencies over ecological timescales and indirectly drive the evolution of longevity. This has important implications for understanding the evolution of life‐history strategies.     

Adaptable mesocosm facility to study oil spill impacts on corals

Although numerous studies have been carried out on the impacts of oil spills on coral physiology, most have relied on laboratory assays. This scarcity is partly explained by the difficulty of reproducing realistic conditions in a laboratory setting or of performing experiments with toxic compounds in the field. Mesocosm systems provide the opportunity to carry out such studies with safe handling of contaminants while reproducing natural conditions required by living organisms. The mesocosm design is crucial and can lead to the development of innovative technologies to mitigate environmental impacts. Therefore, this study aimed to develop a mesocosm system for studies simulating oil spills with several key advantages, including true replication and the use of gravity to control flow‐through that reduces reliance on pumps that can clog thereby decreasing errors and costs. This adaptable system can be configured to (a) have continuous flow‐through; (b) operate as an open or closed system; (c) be fed by gravity; (d) have separate mesocosm sections that can be used for individual and simultaneous experiments; and (e) simulate the migration of oil from ocean oil spills to the nearby reefs. The mesocosm performance was assessed with two experiments using the hydrocoral Millepora alcicornis and different configurations to simulate two magnitudes of oil spills. With few exceptions, physical and chemical parameters remained stable within replicates and within treatments throughout the experiments. Physical and chemical parameters that expressed change during the experiment were still within the range of natural conditions observed in Brazilian marine environments. The photosynthetic potential (F_v/F_m) of the algae associated with M. alcicornis decreased in response to an 1% crude‐oil contamination, suggesting a successful delivery of the toxic contaminant to the targeted replicates. This mesocosm is customizable and adjustable for several types of experiments and proved to be effective for studies of oil spills.     

Differential effects of the crustose Diploschistes diacapsis and the squamulose Fulgensia bracteata on the establishment of a Mediterranean grass species

The interest of the scientific community in biological soil crusts has grown exponentially over the last decades. One of the scientific research interests is the study of the effect of these crusts on plant establishment. Findings in this topic have been controversial, and some differences were attributed to crust types. Biological soil crusts dominated by lichens are common components of Stipa tenacissima steppes in arid and semi‐arid environments of the southern Mediterranean. In the current study, we conducted growth chamber experiments to investigate the differential effects of two lichen species with continuous crustose thalli (Diploschistes diacapsis) and with squamulose semicontinuous thalli (Fulgensia bracteata) on seed germination, root penetration, shoot emergence and seed viability of the tussock grass species S. tenacissima. Our results showed that under laboratory conditions, two distinct lichen species had significantly different effects on the establishment of S. tenacissima. Our findings clearly demonstrated that D. diacapsis significantly decreased germination, root penetration and shoot emergence of S. tenacissima compared to F. bracteata. This can be related to differences in morphological and physiological characteristics between crustose and squamulose lichens. Overall, we suggest that D. diacapsis and crustose lichens generally can act as natural barrier to the establishment of S. tenacissima.     

Testing associational resistance against pine weevils mediated by Lasius ants attending conifer seedlings

Natural enemies attracted to plants may provide those plants with protection against herbivores but may also protect neighbouring plants, that is through associational resistance. Ant attendance may be an important mechanism for the occurrence of such effects because ants can reduce the damage caused by a wide variety of herbivorous insects. Ants have been shown, in a previous field experiment, to decrease the damage caused by the pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), a pest species that causes high seedling mortality in forest regeneration areas. In this study, we specifically tested whether seedlings planted close to ant‐attended seedlings experience associational resistance. We did this under laboratory conditions using the ant species Lasius niger (L.) (Hymenoptera: Formicidae). The feeding damage by pine weevils was significantly reduced on seedlings attended by ants. The neighbouring seedlings, however, did not experience associational resistance. Nevertheless, some associational effects were observed as the number of weevils recorded on both ant‐attended and neighbouring seedlings was significantly lower compared with ant‐excluded seedlings.     

Distribution and human‐caused mortality of Persian leopards Panthera pardus saxicolor in Iran,based on unpublished data and Farsi gray literature

Gray literature and data from unpublished sources can provide important scientific information that has not been published scientifically. The Persian leopard (hereafter leopard) Panthera pardus saxicolor is classed as endangered on the Red List of the International Union for Conservation of Nature and also is one of the least‐studied subspecies of leopard. It occurs in the Caucasus and Central and Southwest Asia. Iran contains more than 75% of the leopard's extant range, and the leopard population in this country serves as a source for neighboring countries. In this study, we determined the distribution and human‐caused mortality of leopards in Iran, by reviewing unpublished data and Farsi gray literature (which includes government reports) between 1 January 2010 and 30 December 2018. We created the most recent distribution map of the leopard in Iran. Our data display that human‐caused mortality of leopard in Iran mostly includes poaching and intentional poisoning, and roadkill.