Bristol Zoo invertebrate conservation

[Onychorhynchus coronatus]

I was reading an issue of the EAZA "Zooquaria" magazine last night that was on the topic of invertebrate conservation in European zoos.

There was quite a lot of information on the ex-situ conservation programes for inverts that have been developed by the Bristol Zoological Society.

This was especially the case for some species such as the Lord Howe Island stick insect, several Partula snail species and the Deserta's Island wolf spider.

I thought that some of it could do with being posted as a thread topic here on zoochat to give an impression of how difficult even the conservation of inverts can be within zoos.

 

[Onychorhynchus coronatus]

Lord Howe Island stick insect

This is from a 2017 article in zooquaria called "Fantastic phasmids" which was written by Bristol zoo's invertebrate curator Mark Bushell who is / was also the EAZA EEP coordinator for the Lord Howe Island stick insect programe:

"In 2015 300 eggs were sent to Bristol Zoo Gardens to begin what was hoped to be the European population for the species, managed closely under an EAZA breeding programme. A dedicated climate-controlled rearing room was established, and several hundred plants (tree lucerne) were grown to feed the resultant nymphs.

The first insects hatched in December, and although we had an excellent hatch rate of over 70 per cent, the nymphs proved very hard to keep alive. After a lot of trial and error involving enclosure changes and additions to the food plant we finally succeeded in rearing just six individuals to adult – three pairs, thankfully!

From these we produced just over 400 eggs. Unfortunately one of our females died quite early on from what appears to be a bacterial infection, but we are currently researching this alongside Melbourne Zoo to see if it is a bigger issue with the management of this species in human care. . Even though this was not the success we were hoping for, it did give us a lot of useful information for future attempts; for a phasmid it is a lot harder than any other species that I and the team at Bristol Zoo Gardens have ever worked with.

From this small batch of eggs we started seeing hatches in March 2017; not as many as we had hoped, but this followed the pattern that Melbourne Zoo saw when they had the first few generations of a lower hatch rate – hopefully this will increase as we go forward.After a few shaky starts we now have a small group of nymphs feeding well, and three confirmed females who we hope to rear to adult some time in November.

We are also in talks with Melbourne Zoo about the possibility of importing another group of eggs to help bolster the population here and, we hope, expedite the process of getting this species established in Europe at EAZA Member collections. Although it is still early days, we are looking for EAZA Members who might be interested in participating in the EEP; there are several things that need to be done to make collections ready to receive the species, and the sooner it can be accomplished the better. Please do get in touch with me if you would like some more information on these truly remarkable animals."

Photo credit to @zoogiraffe

Source: https://www.eaza.net/assets/Uploads/Zooquaria/ZQIssues/Zooquaria-98-web.pdf

 

[Onychorhynchus coronatus]

Deserta's Island wolf spider

This is another article in the same 2017 issue of "Zooquaria" magazine and by the same author (Mark Bushell, the curator of inverts at Bristol zoo) as the previous one on the Lord Howe Island stick insect but this time on the Deserta's Island wolf spider:

"In May 2016, Richard Saunders (Bristol Zoo’s veterinarian) and I attended a three-day meeting and workshop in Funchal, Madeira, alongside experts from the IUCN Species Survival Commission, Madeira University and the Institute of Forest and Conservation of Nature. The strategy we helped to develop follows a holistic view of the conservation programme, including an ex situ programme focused on rearing spiders in human care, and an in situ habitat restoration plan, beginning in 2018, where volunteers from zoological collections will work alongside park rangers on Desertas Grande. The whole ‘project’ will run from 2017–2022 and the official strategy is to be published imminently.

As part of the strategy, 25 individual spiders were collected from the island to form the founder population for the wolf spiders at Bristol Zoo and the process for creating a formal EEP for the species was begun, becoming fully realised in September 2016. The plan for the EEP was to increase the number of holders of the species in Europe over time, with both in situ and ex situ populations considered as a single metapopulation, and transfers would be made between the two, depending on the success of rearing the species at Bristol.

I am delighted to say that although we managed to rear only nine of the animals to adult (this species was trickier than we initially thought and we learnt a lot along the way!), we did produce three males and six females. From these we had four successful egg-sacs, which hatched in July, and some 1500 spiderlings were produced. We have split these into two groups: a less intensely managed population of four separate tanks, which are reared communally depending on which eggsac they came from, and four groups of individually contained animals that are monitored closely for diet, development and health. The former are being used for research into burrow construction, group behaviour and dietary preferences, and the latter will form part of the release population, which we hope will occur in 2018.

We have a couple of small spiderling groups moving to UK collections to help spread the load (ZSL London, ZSL Whipsnade and The Deep) and a couple of others are also in discussion, but we are still looking for new holders for the species. We are anticipating that as it progresses, the potential to produce large numbers of animals for release will probably be needed, so we need to secure as many volunteers as we can for habitat work. The aim is to restore the whole valley by the end of the project, so the more hands, the better!

If you are interested and wish to know more, please don’t hesitate to get in touch with me via the EAZA Member Area website. The species is probably one of the most stunning spiders I have had the pleasure to work with, and they are an excellent ambassador for European invertebrate conservation programmes and for educating visitors on the positive differences that zoos and aquariums can make, especially when we all work together."

Photo credit to @zoogiraffe.

Source: https://www.eaza.net/assets/Uploads/Zooquaria/ZQIssues/Zooquaria-98-web.pdf

 

[Onychorhynchus coronatus]

Interview with Mark Bushell ( Bristol Zoo's Curator of Invertebrates)

This is some excerps of an interview in the same issue of the magazine of an interview with Mark Bushell the invert curator at Bristol zoo about some of the challenges of his work :

DWM: What achievement in the field of invertebrate zoology are you most proud of?

MB: I think one of my proudest achievements has been the work I have put into the Desertas wolf spider (Hogna ingens) conservation programme. I have been involved since February 2013 and it has been a long process, and difficult in places. But to now be in a position where an official strategy has been realised and the ex situ work has begun is an incredible feeling! The team at Bristol has been crucial in the work and it couldn’t have happened without their support, as well as, of course, the IUCN SSC and the various key NGOs and staff in Madeira. In general, though, I am always proud if I can convert someone from not liking invertebrates to being interested in them. It’s crucial to ensure that the next generation can pick up the baton when we pass it to them, so to know that there are people out there willing to do it because of the work we have done is a great feeling.

DWM: Terrestrial invertebrates play a vital role in our ecosystems. Do you think that the public understands the role they play, and do you have any suggestions for EAZA educators for increasing public awareness?

MB: I think that visitors have a good overall appreciation of the role most species play in ecosystems, including invertebrates. However, the fact that you can get up close and personal with a cockroach and have visitors handle them does make it a much more powerful message – you couldn’t do the same with a lion. It is very easy for the ‘actors’ to be the prime focus of the education sessions and quite often visitors come away feeling a certain attachment to the species when they’ve been able to get so close, which I think makes them ideal ambassadors for some of the conservation work EAZA collections participate in. My only suggestion would be to keep doing the amazing work you are already doing, and make terrestrial invertebrates an even bigger part of your sessions!

DWM: Invertebrates are probably not at the top of most visitors’ must-see lists. How do you think we can change that, and do we need to?

MB: I think this question is a touch prejudiced – for example, butterfly houses are probably one of the most popular exhibits at zoological collections. ZSL Whipsnade recently built one that is now their highest scoring exhibit for visitors! They are often key exhibits and a great way of producing an immersive visitor experience; good examples that come to mind are the butterfly temple at Wildlands and the huge dome at Blijdorp. Visitors to zoos and aquariums do like seeing invertebrates; bear in mind the majority of visitors are children, and kids do love bugs! It's very common to hear lots of ‘oohs’ and ‘aahs’ when visitors see a particularly large spider, a group of beetles coloured like jewels or a swarm of locusts. To turn it round, I think that perhaps invertebrates are not as popular with directors; perhaps this is a good opportunity to highlight terrestrial invertebrates as an excellent, low-cost way of showcasing nature’s diversity for our visitors and to educate them on the wonders of nature.

DWM: You’ve spoken elsewhere in the issue about the conservation status of terrestrial invertebrate species. How can EAZA Members help improve the prospects for these species, and do you think we need more programmes for terrestrial invertebrates? If so, which species would you like to see in the EEP structure?

MB: The beauty of terrestrial invertebrates is that generally they don’t need as much space or money to have an effective conservation programme or focus; certainly less than would be required for a group of lions or tigers. The main issue is finding the species that require conservation actions the most and the best methods of applying them for maximum effect, in line with a laid-down strategy with a set guideline for events and goals to be met. The problem is that there are still many, many species that are yet to be assessed for the Red List of Threatened Species and some, even after assessment, are just not in a position for ex situ work. In these cases it’s often best to concentrate on protecting, maintaining or restoring the habitat to help the species (and by proxy many others) survive. The TAG has been working closely with IUCN specialist groups such as the Grasshopper SG and the Spider and Scorpion SG and has helped with the creation of two conservation strategies so far, the Crau Plain grasshopper (Prionotropis rhodanica) and the Desertas wolf spider (Hogna ingens), both of which are featured in this issue, and the former is a prime candidate for the new EEP structure. This is still very much the tip of the iceberg though and there’s a lot more work to be done. I think a lot of species can actually be helped outside the EEP structure with conservation programmes and strategies based on the local taxa; in the UK the tansy beetle (Chrysolina graminis) and the fen raft spider (Dolomedes plantarius) have been subject to some excellent and beneficial work with collections collaborating with local NGOs and experts to help realise the conservation potential of zoological collections. This was something I was really pleased to see highlighted by the Let It Grow campaign, and that it’s not always the big and exotic species that need help – sometimes the most effective conservation work can be done on your doorstep.

DWM: You have four EEPs and one ESB that fall under the TAG. Given the number of offspring produced by some species (such as the Desertas wolf spider recently bred by Bristol, which had over 1000 spiderlings), can you tell us more about the challenges of coordinating these programmes?

MB: Terrestrial invertebrates as a rule do have large numbers of offspring, but this isn’t the biggest issue with population management. As many species lay eggs or egg-masses, it is easy to control the number that hatch simply by disposing of the surplus before they even become a potential issue. With the Desertas wolf spiders this was a bit tricky, as it was the first time they had ever been bred in human care and we weren’t sure what the success rate would be; but I’m delighted to say they proved to be very fecund! The main challenges I have seen so far are that with some species it is very difficult to tell the sexes apart – Frégate beetles (Polposipus herculeanus) for example are almost impossible to differentiate – and in some species the males do not live long once they have reached maturity. Gooty ornamental spiders (Poecilotheria metallica) only live for about 12 months after maturing, so it can be a race against the clock to make sure they are in a breeding position at a collection. I have to say a huge thank you to all collections participating in the ESB for my very short-notice emails asking for transfers across Europe in some cases! Some species aren’t ‘appropriate’ for the EEP structure, usually because they are not of conservation concern that we know of, but the population still needs to be monitored ex situ. All collections want to have lovely big specimens available for display, but these have to come from somewhere and there needs to be a healthy sustainable population to achieve this. The American Zoo Association TITAG has been working hard on a very successful programme called ‘S.W.A.R.M.’ and the Vice-Chairs and I have been in discussions about implementing a similar system here, based on the MON-P level of programme, for various key display species that are held in EAZA Member collections. We’re always on the lookout for willing participants, so please watch this space for updates!

Photo credits to @Javan Rhino.

Source: https://www.eaza.net/assets/Uploads/Zooquaria/ZQIssues/Zooquaria-98-web.pdf

 

[Jurek7]

Lord Howe Island stick insect

I read the story of this insect, which survived on a tiny islet with literally one tree (other articles say few trees).

I sometimes wonder if its single food tree is not the perfect one, and this stick insect could breed better if offered a choice of food plants?

 

[Onychorhynchus coronatus]

I read the story of this insect, which survived on a tiny islet with literally one tree (other articles say few trees).

I sometimes wonder if its single food tree is not the perfect one, and this stick insect could breed better if offered a choice of food plants?

Thats an interesting one @Jurek7, really have no idea about that, I'll check out if there is anything on this topic.

 

[Onychorhynchus coronatus]

I read the story of this insect, which survived on a tiny islet with literally one tree (other articles say few trees).

I sometimes wonder if its single food tree is not the perfect one, and this stick insect could breed better if offered a choice of food plants?

You may well be right @Jurek7

This is from a paper called "Determining host plant preferences for the critically endangered Lord Howe Island stick insect (Dryococelus australis) to assist reintroduction" which tested this hypothesis but to serve the purpose of reintroduction :

"The LHISI has been reared in captivity on plants from a number of Families (Honan 2008), which suggests that the species may have been polyphagous (ability to utilise a variety of Families as host plants) when on Lord Howe Island. Across the Order Phasmatodea, diet varies considerably, with some species having restricted diets, while others are highly polyphagous (Blüthgen et al. 2006). The degree of polyphagy in herbivorous insects depends on various physiological, ecological and morphological factors, and in many species the range of plants consumed changes throughout development (Schoonhoven et al. 2005). Furthermore, studies on stick insects demonstrate that different host plants can affect the longevity, growth rate, reproductive success (Boucher and Varady-Szabo 2005), length of time to maturation and the proportion of nymphs surviving to adulthood (Hsiung and Panagopoulos 1998)."

But Melbourne zoo have apparently already got this covered and have done some trials on it on nymphs :

"The survival of nymphs on different plant species was investigated in trials conducted using nymphs hatched from a stock of 1,092 eggs sourced from the Melbourne Zoo captive population. We used the same 15 plant species (Table 1), with each enclosure (40×40×76 cm) containing cuttings of a single plant species, with two replicate enclosures for each plant species."

Also on adults and subadults:

"We conducted host plant preference trials for LHISI nymphs using the five plant species that yielded the highest nymph survival rates (see above). We used 100 nymphs, with an estimated age of between 3 and 7 weeks, from the Lord Howe Island captive population, which had been feeding on M. howeana. We acknowledge that this familiarity with M. Howeana may have influenced the nymph’s preference for this species. These insects were placed into one of two enclosures (40×40×76 cm) that contained M. howeana cuttings and water dishes."

" the host plant preference trials, we used 30 LHISI subadults that had been transferred from the Melbourne Zoo population, and 30 adults/juveniles sourced from a captive population on Lord Howe Island. These two groups were housed separately in large (67×67×122 cm) enclosures and fed on F. macrophylla columnaris and M. howeana inside the Lord Howe Island Research Station. Individuals used in the host plant preference trials were drawn from these stock populations. Any individuals showing clear signs of stress or illness were not used in any trial. We selected potential host plant species for the preference trials by first documenting diets of stick insects worldwide (Bedford 1978; Tay and Seow-Choen 1996; SeowChoen 2005; Blüthgen et al. 2006) and grouping these plants by Family (as described in Tay and Seow-Choen, 1996). Plants from these Families were then identified from flora lists of Lord Howe Island (Green 1994; Hutton 2010a; J. Bruhl and I. Telford personal communication). This list was then reduced to a shortlist of 15 species (see Table 1) by excluding species that were either uncommon or restricted to the higher regions of Lord Howe Island (I. Hutton personal communication). The preference trials involved placing two different plant species in a 40×40×76 cm enclosure. There were 105 possible plant combinations from the shortlist of 15 plants, with each combination placed in one of 24 enclosures over a 9-day period."

Results / findings were:

"The host plant preference trials revealed a number of plant species that were consumed by the insect and are abundant and/or widespread on the island. The nymph growth and survival trials revealed considerable variation across the 15 host plants examined, but nymphs were able to survive and grow on seven of these plants."

"Our experiments confirmed that the LHISI is polyphagous, with both nymphs and adults consuming, and nymphs surviving on, a variety of plant species from different plant Families. Polyphagy in the LHISI was not unexpected, as flightless stick insects typically have more generalised diets compared with the more specialised diets of stick insects with fully developed wings (Bragg 2001; Junker et al. 2008). However, while polyphagous insects may consume a wide array of plant species, these species are not indiscriminate (Schoonhoven et al. 2005). Similarly, this study demonstrated that the LHISI actively discriminates between host plants, as some species were rarely eaten in the adult preference trials. Nevertheless, polyphagy would clearly increase the prospects of survival for the LHISI if returned to Lord Howe Island because it increases the likelihood of locating suitable host plants."

Source: Determining host plant preferences for the critically endangered Lord Howe Island stick insect ( Dryococelus australis ) to assist reintroduction