Growing old with caterpillars

Posted by Zane McGrath

For the remainder of these summer months I will be searching far and wide for the kawakawa plant. It isn’t the odour emitted by its heart shaped leaves or berries I am attracted to, but the caterpillars hosted by the plant, which I will attempt to adopt and take back to their new home, the luxurious lab at Landcare Research. Although in highlighting the beauty of ecological research, and just to make things more confusing (see earlier posts by Sam and Carolina on ecological complexity), it is not the plant or the caterpillars that will be the main focus of my Masters research, but parasitoid wasps which emerge from the caterpillars.

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The kawakawa plant (top) and kawakawa caterpillar (bottom)

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Parasitoid wasps spend part of their life cycle within a host, such as a caterpillar, and basically eat their way out when ready to pupate, eventually killing the host. Fascinating or down right freaky (have a look for yourself in this video), parasitoid wasps have the ability to act as natural enemies for controlling agricultural pests. For my Masters research I will be focusing on whether Meteorus pulchricornis, a species accidentally introduced into New Zealand, is competing with native species for caterpillar hosts.

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The culprit, Meteorus pulchricornis (Photo: iNaturalist.org) (top) and its cocoon hanging from a kawakawa plant, which is unique to the species (bottom)

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In order to understand this, the caterpillars I collect will be reared until they reach their fate. If I’m lucky, but the caterpillar isn’t, a parasitoid wasp will emerge.

This is where I must hone my husbandry skills. The caterpillars can grow considerably over the period of a month or so before pupating. They will be fed their favourite meal, a kawakawa leaf that is replaced every five to seven days. However, as a parent would say, the growing up process isn’t always a pretty sight. Their homes can become inundated in frass (caterpillar poo), and need I say the larger the caterpillar grows, the larger the frass… but hey, it’s all part of being a parent.

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Frass and a caterpillar

Zane McGrath is an MSc student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. He is supervised by Darren Ward and Graham Walker (Plant and Food Research, Auckland) examining parasitism by exotic species in native environments.

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Marvel takes a risk with Ant-Man whilst I assess the risk of ants

Posted by Anna Probert @AFProbert

Ant-Man. The official superhero of 2015 and my PhD

Ant-Man. The official superhero of 2015 and my PhD

I have a feeling that my beloved study group are going to be gaining quite a bit of interest this year. I would love to say that it is a result of some ground-breaking research I have conducted, but alas. The true reason why I think 2015 is The Year of the Ant, is the impending release (that’s 16th July) of Marvel Studio’s Ant-Man. For those of you that are perhaps not on my level of Marvel fandom, Ant-Man is based on the comic of the same name, where the protagonist has the ability to shrink down to the size of an insect and has superhuman strength and agility. Although in my spare time I’m still trying to discover Pym Particles, my full time role involves being a PhD student here at the UoA and looking at assessing invasive species risk to native ecosystems, using ants as a model.

Unfortunately for our native environment, when it comes to exotic species arriving and establishing in New Zealand, we often let them slide by if they don’t have a perceived potential social or economic impact. As a result, we end up with exotic plant and animal species that become naturalised in the environment. How do they affect the environments in which they naturalise? Well in most circumstances, we don’t really know.

Out in the Hunua baiting for ants. Photo credit Luke McPake

Out in the Hunua baiting for ants. Photo credit Luke McPake

Here in New Zealand we have 29 established exotic ant species (compared to only 11 native species) and very little understanding of how they are influencing the environments in which they live. The Argentine Ant is the species most people would have heard of, as it is a well-known invader worldwide, causing various negative impacts on the environments in which it invades. But what of the other 28 established exotic species we have in New Zealand? What are they doing?

I don’t have the answers… yet, but for my PhD I’m specifically going to be looking at the ways exotic ants influence the invertebrate community structure within different ecosystems, as well as investigating their role in altering ecosystem function. This will involve conducting different manipulative field trials over the upcoming spring/summer seasons – and I’m always on the lookout for field assistants, so let me know if you want to spend a day in nature out with me and the ants.

P.S. Marvel Studios, I am indeed open to sponsorship.

AnnaAnna Probert is a PhD student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is using ants as a model to assess the risk posed by exotic invertebrates to native ecosystems. She is supervised by Margaret Stanley, Jacqueline Beggs, and Darren Ward.

How To Host A Vegetarian Invader

Posted by Jessica Devitt @Colette_Keeha

Recently I just said goodbye to roughly 200 guests. They were not thankful for the hospitality I showed them, they sometimes disliked the meals I served, so much so that they would rather starve than eat, and when I showed them to their new living quarters they would vomit on me to show their disapproval. I still really liked them though. My guests were most probably from Australia, but their descendents are all over the world. Their full name is quite a mouthful, Henosepilachna vigintioctopunctata, but we are on a first name basis now, so I go with the more common ‘hadda’ beetle.

From left:  Enjoying an early lunch of poroporo, hanging together in pyjamas, and baby-sitting

From left: Enjoying an early lunch of poroporo, hanging together in pyjamas, and baby-sitting

The hadda beetle was first discovered in Auckland, New Zealand in 2010 and is a well known pest of a large range of crop species, like potatoes and tomatoes from the Solanaceae family. As part of my MSc, I’ve host-tested the beetles on some native New Zealand Solanaceous plants, like poroporo (Solanum aviculare). Many native New Zealand plants are in decline, and native Solanaceous plants, like poroporo, are important food sources for our fruit-eating bird species. Adding more pressures, like a Solanaceae-munching hadda beetle, could push them further into decline.

To test the beetle’s host range, I did a series of experiments that could not only tell us if the beetle would eat the plants, but more importantly, if the beetle could maintain a self-sustaining population on our native plants. I used the ‘no-choice’ host-testing method, where the beetle is confined to one type of plant and the ‘multi-choice’ test, which allowed the beetles to ‘choose’ to eat or oviposit on a plant from a range choices. Early results show that hadda beetles are indeed happy to munch away and lay eggs on NZ’s native solanums. But to what effect on our plant populations? Watch this space…..

jess Jessica Devitt is a MSc student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is researching the potential host-range of the hadda beetle in Auckland to assess how it might impact on native ecology. She is supervised by Margaret Stanley

When natives go wild: New Zealand… a global supplier of invasive species

Stringer UoA photo

Posted by Lloyd Stringer

After reading Mick Clout’s post on New Zealand’s potential as an Ark for non-native species; a source of genetically diverse species, that could be used to repopulate the historically native ranges from whence they came, I got a-thinking… Is New Zealand a source of invasive species?

In my day job I work on ways to prevent adventive species establishment in New Zealand. I was heartened to discover that Aotearoa has been exporting more than vibrant young kiwis on overseas working holidays.

As a kid I dreamed of a never ending Christmas. That has potential to come into fruition with the spread of New Zealand’s Christmas tree, the pohutukawa, Metrosideros excelsa into European countries. Meanwhile, in South Africa, pohutukawa threaten the ecologically unique Fynbos, already under threat from other invasive species, via prolific seed production leading to dense seedling stands.

A Pohutukawa in full bloom. This species typically flowers from Dec-Jan. Credit: by Ed323 at en.wikipedia (Transferred from en.wikipedia) [Public domain], from Wikimedia Common.

A Pohutukawa in full bloom. This species typically flowers from Dec-Jan. Credit: by Ed323 at en.wikipedia (Transferred from en.wikipedia) [Public domain], from Wikimedia Common.

Another successful export has been the Karaka, Corynocarpus laevigatus. This New Zealand treasure provides a risky food requiring days of preparation to detoxify the seeds prior to eating. Karaka were used in reforestation efforts in Hawaii early in 20th century where it now forms dense stands potentially shading out local, rare endemic plant species.

Possibly some of the less iconic New Zealand species making their way around the globe are the mudsnail Potamopyrgus antipodarum and flatworm Arthurdendyus triangulatus. New Zealand’s mudsnail can reach densities of up to 300,000 individuals per square metre in some rivers, modifying ecosystem processes. Whereas on land, the flatworm, predates on earthworms which could lead to secondary effects such as a reduction in soil quality and a reduction of a food source for native birds.

Perhaps what we are seeing are the New Zealand-sourced winners that could have a chance at surviving in a possible future world that is less species–rich, instead dominated by a few widespread species.

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Lloyd Stringer is an invasive species entomologist at Plant & Food Research and doctoral student in the School of Biological Sciences, University of Auckland, investigating the interactions between eradication tools and Allee thresholds.

 He is supervised by Max Suckling, Jacqueline Beggs and John Kean. Here Lloyd is planning a red imported fire ant field experiment.

Vespula wasps inflict widespread economic and ecological damage

Posted by Jacqueline Beggs @JacquelineBeggs

Jacqueline

What do volcanic eruptions and invasive wasps have in common?

Mt Ruapehu erupting. Photo Craig Potton. http://www.prints.co.nz/page/fine-art/PROD/8973

Mt Ruapehu erupting. Photo Craig Potton. http://www.prints.co.nz/page/fine-art/PROD/8973

A recent study estimates that introduced Vespula wasps cost the New Zealand economy at least $130 million per year – equivalent to the estimated cost of the 1995-97 Ruapehu eruption.

The primary sector, particularly farming, beekeeping, horticulture and forestry bear the brunt of the economic impacts of wasps, but an already stretched health sector also shares the burden. The study did not attempt to quantify the economic impact on the tourism sector, although we know that encountering high densities of wasps puts off many people from outdoor recreation. Vespula wasps are invasive in many parts of the world, but New Zealand has the highest recorded density, not exactly our greatest claim to fame. However, I argue that the ecological impacts of wasps are far more damaging than the economic costs.

New Zealand has no native social wasps or bees, so the arrival of two species of Vespula wasp introduced a novel functional group into our ecosystems. I have spent many years studying the impact and control of wasps in South Island forests infested with endemic, honeydew-producing scale insects. Sugar-coated trees are surely a wasp’s idea of heaven. Native birds, lizards, insects and microbes all feed on honeydew, so when wasps monopolise the resource, many native species miss out. Additionally, wasps are predators of a wide range of invertebrates, attack nestling birds, and disrupt nutrient cycling.

Vespula wasps feed by trophallaxis - food gets passed around the colony making it a good target for control.

Vespula wasps feed by trophallaxis – food gets passed around the colony making it a good target for control.

Social insects are notoriously difficult to control – the social structure of colonies, high reproductive rates and dispersal ability makes management at the population level difficult. Biological control of wasps using Ichneumonid parasitoids has not been successful, although there are other potential agents such as Pneumolaelaps mites which might be more effective. Poison baiting using fipronil is very effective, but currently not commercially available. There are other options for wasp control such as pheromones or ‘RNA interference’ technology. Some of these may be developed as part of New Zealand’s Biological Heritage National Science Challenge, but don’t hold your breath for a single silver bullet arriving in time for next summer.

Unlike unpredictable, sporadic volcanic eruptions, I can reliably predict that for now there will be ongoing economic and ecological harm from Vespula wasps in those parts of the world they have invaded.

Dr Jacqueline Beggs is an Associate Professor in Ecology, School of Biological Sciences, University of Auckland.  She has failed to focus on a single topic; her research covers everything from impact and control of introduced invertebrates, to assessing the role of dung beetles and native bees in ecosystem function, and the recovery of grey faced petrels on a restoration island.

Ecology to genomes and back: Using integrative genomics to gain insights into community assembly dynamics

Centre for Biodiversity and Biosecurity seminar – all welcome.CBB logo

Posted by Jacqueline Beggs

Tuesday, 14th April, 12.30pm
Tāmaki Campus, University of Auckland
Building 733-234

Speaker: Dr Manpreet Dhami, Stanford University, USA

Manpreet groupedManpreet Dhami received her Ph.D. in 2012 from the University of Auckland studying the multi-trophic interactions between scale insects, their symbionts and honeydew consumers. She was supervised by Jacqueline Beggs and Mike Taylor. Manpreet discovered and characterized a novel bacterial symbiont associated with endemic New Zealand scale insects (Dhami et al. 2012), and elucidated the cophylogenetic patterns between bacteria and their scale insect hosts (Dhami et al. 2013a).  She also documented the diverse fungal community associated with honeydew (Dhami et al. 2013b) and showed that honeydew from each scale insect species had a distinctive amino acid and carbohydrate signature (Dhami et al. 2011).

Currently she works as a postdoctoral research fellow at Stanford University in Tad Fukami’s lab, where she is developing an ecological genomics approach to assess the mechanisms underlying microbial community assembly.

Talk outline

Next generation sequencing has revolutionised access to genomics to address key ecological questions such as genetic mechanisms of fitness. I present two case studies that integrate genomics and classic ecological approaches.
Case study 1: Sap-feeding scale insects thrive on a nutritionally poor diet of phloem, possibly enabled by the presence of novel obligate symbionts. Such symbionts, however, cannot be cultured in-situ, hindering further study of their function. We sequenced the genome of one symbiont, establishing its nutritional role in the ecological success of this insect.
Case study 2: Floral nectar hosts a complex community of microbes, such as the dominant Floricolous yeast, Metschnikowia reukaufii. We characterised cell and colony morphology, growth rates and sequenced the whole genome for 23 strains of M. reukaufii. This yeast’s high intraspecific phenotypic variation was correlated with genotypic diversity, potentially contributing to its success as a nectar specialist.

Missing in action since 1921!

by Stephen Thorpe (stephen_thorpe@yahoo.co.nz)

Research Associate, University of Auckland

In 1921, Scutellista caerulea (Fonscolombe, 1832) (Hymenoptera: Pteromalidae) was imported and released in Nelson for the biological control of pest scale insects (Thorpe, 2013). It was thought to have failed to establish. On 17 April 2013, I captured a specimen on vegetation by the pond on the Tamaki Campus, University of Auckland. Despite looking out for adults, I did not see it again until 21 March 2015, when another single specimen turned up (see photos), once again on the Tamaki Campus, just metres away from building 733, where I am based! I shook it out of a garden box of dense Libertia, by the staff shuttle stop (see photo). The question remains unanswered as to whether these specimens are descendants of the 1921 release in Nelson, or else represent a new incursion. The fact that I have only managed to find two specimens in nearly two full years adds some plausibility to the idea that it could have been present in N.Z., unnoticed, since 1921. The proximity of the dates of capture also suggests that there may be a very narrow window of seasonality for adult activity. The species is extremely distinctive. It is a chunky 2 mm long blue wasp, with an enormously developed shield like scutellum, under which it tucks away its wings. Nothing else is like it! The species is known to be a parasitoid of soft scales of the family Coccidae (Badary & Abd-Rabou, 2011), and it would make an interesting project to try to rear it from coccids in Auckland. The Coccidae of N.Z. have been well documented by Hodgson & Henderson (2000).

REFERENCES
Badary, H.; Abd-Rabou, S. 2011: Role of pteromalid parasitoid Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae) for biological control of the soft scale insects (Hemiptera: Coccidae) in Egypt. Egyptian academic journal of biological sciences, 4(1): 49-58. http://entomology.eajbs.eg.net/pdf/vol4-num1/5.pdf

Hodgson, C.J.; Henderson, R.C. 2000: Coccidae (Insecta: Hemiptera: Coccoidea). Fauna of New Zealand, (41) http://www.landcareresearch.co.nz/publications/books/fauna-of-nz-series/extracts/fnz41

Thorpe, S.E. 2013: Scutellista caerulea (Fonscolombe, 1832) (Hymenoptera: Pteromalidae), new to New Zealand for the second time! Biodiversity data journal, 1: e959. doi: 10.3897/BDJ.1.e959

Scutellista - recently recorded in Auckland after decades of no sightings.

Scutellista – recently recorded in Auckland after decades of no sightings.

A new Australian ladybird for New Zealand!

by Stephen Thorpe (stephen_thorpe@yahoo.co.nz)

Research Associate, University of Auckland

I have only very recently discovered that the courtyard in front of the Human Sciences Building (HSB), on the University of Auckland City Campus, has plantings of all sorts of interesting and unusual exotic plants, some of which have associated insect herbivores. Some cycads there are infested with various scale insects. On these cycads, I have found two adults of a ladybird new to New Zealand. The adult isn’t going to win any ladybird beauty pageants! It is tiny and uniformly black (see photo on left). However, the structure of the head is quite distinctive, especially the reduced antennae, hidden under a shelf (see photo on right). Based on adult morphology, it clearly belongs to the genus Telsimia, which was hitherto not known to be present in New Zealand. Identification at the species level is a bit trickier, but I have tentatively determined it as Telsimia subviridis (Blackburn, 1892), a common Australian species (Ślipiński, Pang & Pope, 2005). Species in this genus are predators of scale insects, particularly armoured scale (family Diaspididae). Larvae of species in this genus are known to have long waxy projections (Park & Yoon, 1993). I have seen three larvae fitting this description in the HSB courtyard (see middle photo), but not on the cycads! The larvae were all on the trunk of an Acacia tree, several metres away from the cycads. I have not seen larvae like this elsewhere.

New ladybird species in town. Left: adult Telsimia ladybird, centre: Telsimia larva, right: close up of adult Telsimia head.

New ladybird species in town. Left: adult Telsimia ladybird, centre: Telsimia larva, right: close up of adult Telsimia head.

REFERENCES
Park, H.-C.; Yoon, I.-B. 1993: Telsimia nagasakiensis Miyatake, an unrecorded species (Coccinellidae, Coleoptera) from Korea, with larval description and biology. Korean journal of entomology, 23(4): 277-281.

Ślipiński, A.; Pang, H.; Pope, R.D. 2005: Revision of the Australian Coccinellidae (Coleoptera). Part 4. Tribe Telsimini. Annales zoologici, 55(2): 243-269  .

A newbee in town!

by Stephen Thorpe (stephen_thorpe@yahoo.co.nz)

Research Associate, University of Auckland

The bees of New Zealand have been documented quite recently (2007) by the appropriately initialled B. Donovan. However, another one has recently turned up. So far, it is only known in N.Z. from six males collected by me, all on the Tamaki Campus, Auckland. It is a masked bee (see photo) belonging to the vast genus Hylaeus.

Keep on the lookout for this new bee in New Zealand. No females have been found yet.

Keep on the lookout for this new bee in New Zealand. No females have been found yet.

It belongs to a subgenus, Gnathoprosopis, not otherwise represented in N.Z. I have identified it as Hylaeus euxanthus, a common and widespread species in Australia (see Houston, 1981). MPI are in the process of getting the ID validated. The first two specimens captured had black mandibles, which is unusual for the species in Australia, and therefore put the ID in a little doubt, but subsequent specimens clearly have yellow mandibles. It would be useful to find females, which will have less of a yellow mask, but so far no luck.

The species may be of some interest to those studying pollination ecology in N.Z. There is clearly a lot of scope for further research on this species in N.Z. How widespread is it? Is it spreading? Will it compete with native bees? What are its flower visiting preferences? My specimens were found visiting kanuka flowers in November and December, and sweet fennel flowers in late February. The males have a pair of tubercles on the underside of the gaster (abdomen), which are variably developed. They are clearly visible in the lower photo. The species is immediately distinguished from other Hylaeus in N.Z. by having the first antennal segment (scape) short and entirely yellow.

REFERENCES

Donovan, B.J. 2007: Apoidea (Insecta: Hymenoptera). Fauna of New Zealand, (57) www.landcareresearch.co.nz/publications/books/fauna-of-nz-series/extracts/fnz57

Houston, T.F. 1981: A revision of the Australian hylaeine bees (Hymenoptera: Colletidae). II. Australian journal of zoology, supplementary series, (80) doi: 10.1071/AJZS080

The mystery of the Australian ladybird, Rodolia koebelei

Australian’s are well known for seizing an opportunity when in foreign lands, but is that the case for this new arrival in New Zealand?

by Stephen Thorpe (stephen_thorpe@yahoo.co.nz)

Research Associate, University of Auckland

Rodolia koebelei (Coleoptera: Coccinellidae) is a fairly distinctive looking ladybird, about 3 mm in length. The extent of black markings on the elytra varies from none to that shown in the photo. This Australian species was reported as validated new to Rodolia koebeleiNew Zealand by Biosecurity New Zealand (2006). Nobody knows how it got here. On 19 February 2015, I found a single specimen, on a cultivated Hebe, on the Tamaki Campus. So far, this is the only specimen I have seen on campus, and I have only ever seen two others elsewhere in Auckland, though one of those two was at the adjacent Morrin Reserve. Very little is known about this species in New Zealand. In particular, mystery surrounds what it preys on. According to one overseas study, larvae of R. koebelei could only be reared to adults on Icerya koebelei and when they were offered other species of scale insect (I. purchasii, I. aegyptiaca, or I. seychellarum), they failed to feed and all died (Sands & Van Driesche, 2004). The mystery is that I. koebelei is not known to be present in New Zealand. Perhaps it actually does prey on the closely related cottony cushion scale (I. purchasi), which is present on campus. If so, this is evidence that the results of host range testing experiments need to be treated with caution. At any rate, there is plenty of scope for further research on this ladybird in Auckland. Larvae need to be located, and the likely prey needs to be determined. The species could potentially be useful as a biocontrol agent for cottony cushion scale, in the same way as the cardinal ladybird (Rodolia cardinalis), the latter of which now appears to be very rare in Auckland (I haven’t seen any on campus). Continue reading