Invertebrate Biology最新文献

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.

Our understanding of how sea anemones reproduce in the equatorial Central Indo-Pacific region remains poor compared to other marine regions. Here we report the gametogenic cycles of Phymanthus pinnulatus, a zooxanthellate sea anemone found throughout the Indo-Pacific tropics. Observations were based on 41 individuals collected in Singapore. We found P. pinnulatus to be gonochoric, with an equal sex ratio of 1:1. Phases of oogenesis and spermatogenesis were detailed for the first time in P. pinnulatus, and were consistent with phases in other actiniarians. Females with pedal disc diameters <10 mm were found to asynchronously produce oocytes. We also found that trophonemata were associated with both oocytes and spermaries during gametogenesis. In Singapore, the periods during which gametes matured in each sex of P. pinnulatus appeared to overlap. We were unable distinguish whether spawning was annual or continuous in P. pinnulatus. Our observations on the occurrence of maturing and matured gametes in P. pinnulatus were similar to those reported for other species within the Central Indo-Pacific. It also coincided with the multispecies spawning of scleractinian corals in Singapore. This study contributes to the growing body of work focused on the biology of tropical actiniarians in the Central Indo-Pacific region.

Hands-on experience is critical to teaching invertebrate zoology, as students are unfamiliar with many animals and theoretical concepts are sometimes difficult to assimilate. As part of a fully online course, we decided to give students a box of take-home materials so that they could do hands-on work in their homes under the guidance of the teacher or at their own pace following the lecture scripts and presentations. The box contained whole specimens fixed in ethanol for observation and dissection, dried material such as skeletons and shells, and microscope slides. We also included a USB digital microscope to facilitate visualization of details and slides. The experience was very satisfying and proved to be not only a good alternative for mandatory online classes in times of pandemic, but also an interesting resource to supplement face-to-face classes.

The use of new technologies including personal mobile devices has become an indispensable tool in our daily lives, and thus its presence in education is becoming ever more ubiquitous. In the current scenario imposed by the COVID-19 pandemic, in which in-person presence in classrooms has been enormously reduced at all educational levels, the use of mobile learning and cutting-edge methods can greatly improve the way students learn and enhance their online-learning experience. Mobile applications, combined with extended reality technologies such as virtual reality (VR) and augmented reality (AR), are powerful tools that connect real and virtual environments and allow higher interaction for the user. We have leveraged the advantages of mobile learning and extended reality technologies to develop a series of mobile applications and associated educational activities for university-level courses involving invertebrate zoology field work. In particular, we have developed (a) a VR SCUBA diving video to explore the diversity of a marine protected area; (b) an AR mobile app to visualize 3D models of marine invertebrates; and (c) a mobile-based catalogue to explore the terrestrial biodiversity of one of the most diverse regions of Spain. Here we provide detailed information describing the design and creation of these tools, as well as their application in class, to facilitate and encourage their use in higher education. Despite the relatively recent application of these technologies in education, they have an enormous potential: they improve student motivation and learning, can be adapted to different learning styles, reduce social inequalities, and facilitate inclusiveness and diversity practices in the classroom.

We present an exercise for counting trematode cysts on mudsnails that can be implemented as a field-based project in course work by students or by volunteers. The exercise involves the digenetic trematode Pleurogonius malaclemys, which infects diamondback terrapins (Malaclemys terrapin) as its definitive host, and eastern mudsnails (Tritia obsoleta) as its intermediate host. The trematode forms macroscopic metacercarial cysts on the shells and opercula of the mudsnails, and the life cycle is completed when terrapins ingest the intermediate hosts with cysts. Previous research has suggested that quantifying cysts on mudsnails can be a relatively simple method to estimate terrapin population sizes where terrapins co-occur with mudsnails. Three non-professional scientist groups (including students and volunteers) were tested in their estimates of prevalence and intensity data compared to verified cyst counts. Prevalence data were relatively accurate (~76–78%) and reliable (68–89%) across the groups. The intensity of cysts (on shells and opercula of mudsnails) were mostly within 12% of the verified counts (total mean intensity of 1.81–2.97 cysts/parasitized mudsnail) but varied significantly in two cases due to false positives (likely due to sand grains or debris scored as cysts) or negatives (likely due to missed cysts behind the operculum). The exercise can be completed as a lab or series of labs in courses, and data from such projects could be used in terrapin conservation efforts, particularly in helping scientists determine where terrapins occur. We discuss modification of the exercise for other trematode species in regions around the world and hope this expands recognition by the public of the important role of parasites in ecosystems.

Secretion of an extracorporeal hydrogel is a common defensive strategy employed by many aquatic invertebrates including several species of sessile rotifers. Here, we provide a comparative study of the ultrastructure of the gelatinous secretions of four species of Superorder Gnesiotrocha (Monogononta): Conochilus unicornis, Collotheca ferox, Stephanoceros fimbriatus, and Stephanoceros millsii. Additionally, we use differential staining and enzyme degradation assays to explore the chemistry of the gelatinous tube of S. fimbriatus. At least three types of secretions are produced by these four species: an external gelatinous tube, a thick glycocalyx, and an adhesive peduncle. These three different secretions all have a fibrous appearance, but each has different electron densities, fiber thicknesses, and glandular origins. The gel tube, which is likely secreted by pedal glands, has a highly hydrated framework of mesh-like fibers with thick internal and external laminae that differ slightly among species. Chemical staining suggests that the gel tube is composed of glycoproteins with a high content of sulfonic groups and limited or no obvious lipids or cationic proteins. This tube is resistant to chemical and enzymatic digestion. The proteinaceous glycocalyx is secreted by the syncytial integument and has various densities and thicknesses among species. The peduncle is an adhesive attachment that connects a rotifer's foot to a substratum, or, in some species, to conspecifics as part of a colony. The secretion is highly electron dense and contains membrane-bound vesicles; it appears to be derived from a different set of pedal glands than the hydrogel tube. The different chemistries and anatomical origins of the three gelatinous secretions suggest an independent evolutionary history for each.

Patterns of population biology and community structure can be studied by looking closely at the ontogeny and reproductive biology of reef-building organisms. This knowledge is particularly important for Caribbean octocorals, which seem to be more resilient to long-term environmental change than scleractinian corals and provide some of the same ecological services. We monitored the development of the black sea rod, Plexaura homomalla, a common, widely distributed octocoral on shallow Caribbean reefs, from eggs to three-polyp colonies over the course of 10 weeks. Gametes were collected ex situ on St. John, U.S. Virgin Islands, during spawning events that occurred 3–6 days after the July full moon. Cleavage started 3.0 hr after fertilization and was holoblastic, equal, and radial. Embryos were positively buoyant until becoming planulae at 3 days after fertilization. Planulae were competent to settle 4 days after fertilization. Symbiodiniaceae began infecting polyps ~8 days after fertilization. Overall, development was typical for Caribbean octocorals, except for an increase in the number of embryos between 3.5 and 6.0 hr after fertilization.

There is a great importance for undergraduate biology students to study organisms in their natural context. Safety concerns surrounding the global COVID-19 pandemic prevented Marine Invertebrate Zoology students at the University of Tampa from participating in traditional faculty-led field trips during the Fall of 2020. Instead, students were assigned to conduct a diversity-focused field trip on their own and report their findings. Here we describe considerations and methods for creating a safe and valuable self-guided field trip assignment for upper-level invertebrate zoology students. These methods are adaptable for a variety of different habitat types and can be conducted with little to no special equipment or training. Students were successful in completing this assignment and found it highly enriching.

We implemented a new video project in a marine invertebrate zoology undergraduate class. The project required students to produce 3–5 min videos about a particular invertebrate or any aspect of invertebrate biology they were interested in. The development of this assignment was prompted by the limitations for lab activities due to COVID-19 and three short-term campus closures in response to threats of inclement weather. This assignment can be completed individually on a flexible schedule, without physical access to campus, and culminates in an Invertebrate Film Festival during the last lab period. The project was assigned at the start of the term with only minimal instructions to promote creativity. Students completed the project over the course of the 14-week semester, with several checkpoints, most notably a peer review of the movie script 2 weeks prior to the due date. To support the video production, students were encouraged to attend workshops and schedule individual tutoring sessions offered by the Studio in the campus's Center for Academic Learning Support. Surveys at the beginning and the end of the semester revealed that the perception of the video project was overall positive, although some students were apprehensive in the beginning. Video topics, techniques, and software used by students varied widely, but overall the video quality exceeded our expectations. Many students took pride in their videos and agreed to make them available as supplementary material for this article. If we repeat this assignment in future semesters, we will streamline the peer review process and possibly offer short video tutorials for video-editing software.

An entirely online upper-division university marine invertebrates course modeled after a field experience-intensive course that also provided interaction with live animals and research experience was offered at Rosario Beach Marine Laboratory in the summer of 2020. We describe online methods we used for providing field experiences to students participating online, as well as a workstation and interactive method for identification and detailed anatomical examination of live macroinvertebrates with students. Students were also involved as active participants in a field research project. Nearly all of the equipment involved is inexpensive or readily available in most university biology laboratories or classrooms.