invertebrates

An Arachnophile's Bible

"Spiders!" I yelled, "Oh my god, spiders!"

Such an utterance may well epitomise the human relationship with the order Araneae - their hairy bodies and scuttling character a visceral trigger of fear and loathing for many. However, in this case the above words were shouted not in contempt or aversion but instead, excitement and glee. They were the words I spoke when this book was first presented to me.

Image: CSIRO Publishing

Image: CSIRO Publishing

Natural history field guides exist for a plethora of taxa in Australia. There are, of course, numerous bird guides from various authors, each with their own status in the birdwatching community. There are guides on reptiles and frogs and guides on mammals, and there are guides on invertebrates too. Waterbug books help people to identify aquatic macroinvertebrates, while other guides such as Insects of South Eastern Australia aim to give people an idea of the ecology and behaviour of our smaller earthlings. Butterfly guides often take the cake when it comes to illustration and photography and there are numerous publications for an enthusiast to choose from. Yet, though my bookshelf can aid you in sorting swallow-tails from skippers and distinguishing dunlin from dowitcher, I have long battled to find an equivalent resource for the "eight-legged freaks" I so love.

As Robert Whyte and Greg Anderson, authors of A Field Guide to Spiders of Australia, attest: "In 2007 if there had already been a modern field guide with colour photographs...this project would not have been started." It was around this time that my own interest in spiders- or "arachnophilia", as the authors put it - was beginning to emerge. This time in my life stood in stark contrast with the years of my childhood when I felt very differently towards them. I have vivid memories of waking to find a spider crawling on the ceiling above my bed on a number of occasions. In my young mind's eye, they were enormous and sinister-looking beasts and I was quick to call on my father to dispatch them.              

Yet, years later, something changed. My knee-jerk aversion to spiders was replaced with a sense or curiosity, which was soon followed by a strong admiration and enthusiasm for these creatures. What caused this change?

The guide dubs this guy a shaggy, red-headed house hopper. Works for me. He's pictured here with another jumping spider for a meal.  Image: Chris McCormack

The guide dubs this guy a shaggy, red-headed house hopper. Works for me. He's pictured here with another jumping spider for a meal. Image: Chris McCormack

I see you!  Image: Chris McCormack

I see you! Image: Chris McCormack

A camera. Or, more to the point, the new way in which it allowed me to view spiders. Suddenly I was able to take a photo of a web-weaving member of my household and look upon their minute features in detail. For the first time I could really see them; their eyes, their fangs, their palps, and more. Far from causing visceral fear or disgust, my new-found ability to capture their likeness stirred in me a sense of intrigue and affection. I pondered their existence and their stories. Why did certain species look and behave as they did, and what had brought this particular individual to this place at this time? Like many people who spend time observing animals, I began to notice the quirks of different genera. I was delighted by the curiosity of jumping spiders and found the shy, reclusive nature of black house spiders endearing. These scuttling, crawling, jumping, spinning creatures were neither sinister nor beastly: they were fascinating, beautiful, and even - as the authors put it - "cheeky and disarming".

While some have hypothesised that the fear many of us have of spiders is an evolutionary adaptation - a form of biophobia - Whyte and Anderson make plain their theory that such aversions are learned. Whatever the case, it is clear these fears and prejudices can be unlearned, as I (and many others who have battled with far more crippling spider-based anxieties) can attest. My adolescent indulgence in photography completely changed the way I view spiders, and so I’ve no doubt that a guide such as this, replete with stunning photographs of professional quality, can do the same for many others. Here, you have an opportunity to look confidently upon a world you might rarely dare to glance at in other circumstances. Be bold, and with this book as your guide, challenge your perspective of spiders, not only for their sake but because "To be able to identify and understand these creatures will surely make the time you spend in natural places more vibrant and meaningful."

Helpis sp.   Image: Chris McCormack

Helpis sp. Image: Chris McCormack

Lynx spiders prowling the undergrowth.  Image: Chris McCormack

Lynx spiders prowling the undergrowth. Image: Chris McCormack

For those already willing to give spiders a chance and who are looking for a practical means to identify them, this too is your book. While no physically lift-able book could hope to photographically catalogue the some 4,000 known Australian spider species, this guide is nonetheless impressively comprehensive. Its some 1,300 colour photographs will provide you with an indispensable resource for identification.

With that said, you might wonder when such a book would be of use. Well, aside from being handy for knowing the names of your many house guests, the guide will provide you with the ability - and motivation - to seek out and explore species new to you, and possibly even new to science! As the authors note, we've barely scratched the taxonomic surface of Australian spider genera: there could be as many as 20,000 species in all. If you're unsure of how you might stumble upon an opportunity to put this book to good use, consider as the authors have that there may be as many as 500 spiders in any square metre of grassy field. If 500 spiders per square metre of field isn't reason enough to use a spider field guide I don't know what is...

A huntsman waits for nightfall.  Image: Chris McCormack

A huntsman waits for nightfall. Image: Chris McCormack

For existing arachnophiles, this book is a must-have and will become a go-to resource for your passionate pursuit of the palpy. For those not yet in love with spiders - even those deathly afraid of them - I implore you to give it a chance. As renowned nature writer Tim Low states in the book's foreword:

"Submitting to the pages that follow could change your life."

A Field Guide to Spiders of Australia is due out in June. Head to the CSIRO Publishing website to pre-order your copy.          


Chris McCormack
Chris graduated from The University of Melbourne with a Master's of Science in Zoology and has spent the past two years working for the Victorian government delivering citizen science projects. He is the Managing Director of Wild Melbourne and pursues his interests in science and natural history through the mediums of film, photography and written communication. 

You can find him on Twitter @Chris_M_McC


Banner image courtesy of Chris McCormack.

Small Systems Are Go: How Tiny Communities Provide Invaluable Services

This is a guest post by Michael Smith.

Relationships are a part of our everyday existence. They are an inescapable reality whether they be between humans or with a pet, or with non-living entities such as food or exercise. Although human beings are intelligent and creative in many facets of their living and problem-solving, we are simply not capable of performing all the tasks essential for survival. Like all animals that exist on this fragile globe, we rely on services that other organisms provide for our survival. More often than not, these services are the result of an ecosystem rich in diversity. To help illuminate this point, let us explore how plants, which humans rely on for edible sustenance, depend on communities for their existence.

Plants have the fantastic and extraordinary capacity to harness energy from sunlight. When a plant splits photons, the energy released is used by flora to breakdown CO2, water and oxygen into carbohydrates. Evolution has enabled plants to perform this task because it is a way of storing energy. Plants can then choose to use the energy contained within the carbohydrate compound at a later date.

Energy alone is not enough to grow and prosper though. Plants also need minerals to build proteins for cellular structures. In order for plants to obtain mineral nutrients, many types of flora rely on insects and other small biota for underground love. Worms and burrowing insects break down organic matter into nutrients available for plant consumption. Furthermore, by travelling up and down the soil profile they create gaps for nutrients, water and oxygen to flow towards the plant’s root zone. As a result, plant growth and therefore human survival is reliant on insects providing aboveground and underground services.

An Australian common skink hiding amongst leaf litter  - Skinks are a wonderful predator in forest ecosystems. By feeding on larger invertebrates, including moths, crickets, flies and grasshoppers, they ensure that a population explosion of an insect species does not occur.  Image: Michael Smith

An Australian common skink hiding amongst leaf litter - Skinks are a wonderful predator in forest ecosystems. By feeding on larger invertebrates, including moths, crickets, flies and grasshoppers, they ensure that a population explosion of an insect species does not occur. Image: Michael Smith

Plants are not simply limited to underground interactions with insects. Fungi and bacteria also help plants flourish. Fungal hyphae (a network of underground filaments), for example, reach far and wide searching for nutrients to concentrate and store. Excess nutrients are exchanged with carbohydrates from some plants, a sort of festive fungi barter system. In addition, fungi interacting with plants can trigger the release of chemicals, which prevent insects from attacking the plant and, in some cases, can signal to predatory insects that a feast of arthropods awaits them on a plant’s leaf plateau.

Nitrogen-fixing bacteria, on the other hand, change nitrogen gas into compounds useable by plants. In the first phase, non-symbiotic bacteria fix nitrogen gathered from the atmosphere with other elements to form nitrogenous compounds (inorganic compounds usable by plants). In the second phase, symbiotic bacteria living within root nodules of a leguminous plant exchange the fixed nitrogen for sugars. This interconnected exchange makes the production of the humble lentil a possibility. Therefore, it seems that for humans to eat fantastic plants full of protein and carbohydrates, we are reliant on skills we cannot replicate, and communities full of tiny life forms!

Exploring the relationships involved in a living, micro community of interconnection can be exciting and rewarding. Not only is it fascinating to find out about previously unknown relationships, but it also gives humans an opportunity to help communities perform more efficiently. A classic example is feeding your soil organic matter. Compost does much more than simply feeding subterranean life. It also binds itself to clay particles, loosening and aerating soil in the process. As a result, rain and insects can transport nutrients to a plant’s root zone with a lot less resistance.

Now, we all know about honey bees and pollination, but consider the fact that solitary bees, hoverflies and blowflies in particular scenarios are considered better pollinators. In wildflower patches throughout Victoria, the most common insect you will find, by a considerable factor, is the hoverfly. This fantastic insect masquerades as a bee by displaying fabulous yellow and black stripes. It does this to convince predatory insects that it’s a bee, reducing the chance of an attack. Hoverflies are the greatest pollinators of Melbourne wildflower patches, transporting pollen to and from a profusion of indigenous wildflower species. As well as pollination, hoverflies have an insatiable appetite for aphids and therefore are deemed a beneficial insect to have in farms and backyards.

A native Australian ‘short tongued’ bee resting on a chocolate lily.   Image: Michael Smith

A native Australian ‘short tongued’ bee resting on a chocolate lily. Image: Michael Smith

The second most common group of pollinators in Melbourne’s wildflower patches includes bees and wasps. Bees are capable of seeing UV light and are subsequently attracted to colours closer to the UV spectrum, including blues and purples. Native Wahlenbergia and Comesperma plants evolved alongside the native bees of Melbourne, before the introduction of the European honeybee. These plants are not only brilliant shades of blue and purple but have smaller flower heads requiring native Australian bees, with shorter tongues, to pollinate them in order to not pierce their tube.

On the contrary, blue-banded bees perform a special behaviour called buzz pollination. By shaking their body violently with powerful wing muscles, pollen is dislodged from plants, such as species in the Dianella genus, which hang onto their pollen very tightly. In many parts of the world, honeybee populations have been decimated by neonoictoid pesticides (that are intended to kill harmful insects) and the Varroa mite. As a result, we may become even more reliant on native insects. In fact, it is plausible we will rely on them to pollinate a significant proportion of our commercially grown crops, as well as our wildflower patches and forest species.

Spider on Daisy  - It is not uncommon to see small spiders on top of daisy seed heads. They are waiting patiently for a pollinator, such as a small bee or butterfly to land on the daisy. Once they have landed, the spider will attack.  Image: Michael Smith

Spider on Daisy - It is not uncommon to see small spiders on top of daisy seed heads. They are waiting patiently for a pollinator, such as a small bee or butterfly to land on the daisy. Once they have landed, the spider will attack. Image: Michael Smith

So how can we help these communities of helpful and talented insects? One way is to plant native wildflower patches in your backyard and ideally link your patch to those of your neighbours. Animals love to travel along corridors and insects are more likely to see a food source if the patch is large. Convince your neighbour that native bees will then pollinate their tomatoes and hoverflies will attack the aphids on their brassicas!

You can also build insect motels. Air bee-and-b! These engineered homes are a place for insects to seek shelter, escape from predators, hibernate and allow their larvae to grow. Insects are quite particular about their homely requirements. It is therefore essential to use the right materials to attract the beneficial bees you are after. Blue-banded bees, for example, naturally make their homes in clay banks, and resin bees in branches; therefore, make holes in similar materials when constructing a hotel.

Imperial blue butterfly  - Ants form a mutualistic relationship with the caterpillar of this species. They protect the caterpillars from predators and in return feed on the surgery substance which exudes from the caterpillar.  Image: Michael Smith

Imperial blue butterfly - Ants form a mutualistic relationship with the caterpillar of this species. They protect the caterpillars from predators and in return feed on the surgery substance which exudes from the caterpillar. Image: Michael Smith

Currently exhibiting at Lentil as Anything in Thornbury, my partner Fiona Mitchell and I are spreading a story about relationships and communities. The story is mostly based around wildflowers in Northern Melbourne; for example, Boomers Reserve, in Panton Hill, which has a profusion of beautiful flowers.

We believe that visual media (photography, documentaries and paintings) are a great way to create an initial interaction with a community member, and to spark interest about this fascinating subject area. From there, a message of deeper understanding can be attached (in our case, with blurbs attached to art work), which will hopefully result in further questions about the fascinating world of ecosystems and insect communities.


Michael Smith is a trained ecologist that currently works in bush regeneration, habitat engineering and environmental education. He is passionate about community engagement and teaching the importance of biodiversity. 


Banner image courtesy of Michael Smith. 

Living a Double Life

There is a spectacular amount of biological diversity in the sea. Most of it usually goes by unnoticed.

The vast majority of marine species live a double life split across two (or sometimes more) distinct life stages. Marine species usually begin life as a small larva, typically less than 1mm long, before undergoing the process of metamorphosis, where abrupt morphological and functional changes occur, to develop into a drastically different adult.

The life cycle of the sea squirt  Pyura dalbyi  (image order clockwise: fertilised egg, hatching larva, free-swimming larva, newly settled larva, two-month old adult, and fully reproductive adult).  Images: Evatt Chirgwin

The life cycle of the sea squirt Pyura dalbyi (image order clockwise: fertilised egg, hatching larva, free-swimming larva, newly settled larva, two-month old adult, and fully reproductive adult). Images: Evatt Chirgwin

Most of the life we encounter during our ventures into the ocean and the seafood that ends up on our plates represent the adult stages of species’ life cycles. The tiny size of larvae means that they generally go unseen without the aid of a microscope. While larvae tend to go unnoticed by the everyday observer, they account for arguably the most fascinating diversity and ecology in the sea.

It’s a hard life for larvae - they’re small critters in an enormous environment. Yet despite their size, larvae are far from being simple, helpless drifters. They have evolved a range of adaptations that enhance their chances of survival. For instance, many avoid predators by hiding at great depths during daylight hours, only rising to the more productive and food-abundant shallow waters under the cover of night. Additionally, several species also exploit stratified horizontal currents as a sort of conveyor belt, which allows them to migrate between near-shore and offshore habitats to suit their needs at different times.

Marine larvae are remarkably diverse members of ocean ecosystems.  Images: Evatt Chirgwin & Wikimedia Commons

Marine larvae are remarkably diverse members of ocean ecosystems. Images: Evatt Chirgwin & Wikimedia Commons

Seemingly the most important role of larvae is that it's typically the stage in an individual critter’s life where the largest or only (for species with a sessile adult stage) dispersal occurs. Some larvae travel immense distances, covering hundreds of kilometres over the course of months, while others travel only a few metres in a few hours. Crucially, the larvae need to use this dispersive period to find a habitat with sufficient resources and mating opportunity or escape the trappings of a poor habitat. This allows for success in their subsequent adult stage. Consequently, many larvae have adapted intricate ways to assess habitat quality using chemical cues in the water column or the biofilm (a bacterial layer covering solid surfaces) to obtain information on vital factors, such as food, oxygen, predators, and possible mates.

Larvae of species such as the bryozoan  Bugula neritina  have been shown to use chemical cues in biofilm to assess habitat quality.  Images: Evatt Chirgwin

Larvae of species such as the bryozoan Bugula neritina have been shown to use chemical cues in biofilm to assess habitat quality. Images: Evatt Chirgwin

Following metamorphosis, an adult often shows remarkably little resemblance to its larval stage. However, there is a good reason for this disparity, as it reflects the fundamental role of each life stage. Whilst the larval stage is typically tasked with undergoing dispersal, the adult stage must achieve reproduction. The variations between adults and larvae have repeatedly been extended due to the two stages typically occupying vastly different environments and ecological niches. For instance, many species live their larval stage in the pelagic before settling and living their adult stage in the intertidal zone. In doing so, many face huge changes in factors such as temperature, oxygen, and salinity.

The tubeworm  Galeolaria caespitosa  spends its first few weeks of life as a free-swimming pelagic larva before settling and living in the intertidal as an adult.  Images: Evatt Chirgwin

The tubeworm Galeolaria caespitosa spends its first few weeks of life as a free-swimming pelagic larva before settling and living in the intertidal as an adult. Images: Evatt Chirgwin

An unfortunate consequence of being unnoticed is that you can all too easily slip into trouble. Larvae are nearly always more sensitive to environmental stress than their more visible adult counterparts. Consequently, the actual effect of anthropogenic stressors such as climate change and pollution on marine populations can often be not truly appreciated - at least not immediately. With environments globally changing at increasingly faster rates, it’s important that we work to understand and manage all parts of species’ lives, and not just the parts most visible to us.


Evatt Chirgwin

Evatt is an evolutionary ecologist whose research focuses on how natural populations can adapt to environmental change. He is currently undertaking his PhD at Monash University.

You can find him on Twitter at @EvattChirgwin


Banner image courtesy of Evatt Chirgwin.

The Little Things That Run The City

This is a guest post by Luis Mata. 

…let me say a word on behalf of these little things that run the world.

This quote was part of an address given by E.O. Wilson on the occasion of the 1997 opening of the invertebrate exhibit of the National Zoological Park in Washington D.C. The ultimate objective of Wilson’s address was to stress the urgent need to recognise the importance of insects and other invertebrates for humanity. He was keen to see that efforts aimed at the conservation of biodiversity were beginning to include non-vertebrate animals. In his words:

‘A hundred years ago few people thought of saving any kind of animal or plant. The circle of concern has expanded steadily since, and it is just now beginning to encompass the invertebrates.’

With The Little Things that Run the City - a close research collaboration between the City of Melbourne’s Urban Sustainability Branch, RMIT University’s Interdisciplinary Conservation Science Research Group and nine other academic and government organisations - we sought to expand this circle so that it may also encompass the conservation of insects in urban environments. We were driven by the motivation to ‘say a word on behalf of the little things that run the city’. 

The Little Things that Run the City, Mata et al. 2016.  Artwork: Kate Cranney

The Little Things that Run the City, Mata et al. 2016. Artwork: Kate Cranney

How many insect species live in your city? How are they distributed amongst the city’s green spaces and habitats? What are the ecological processes they perform and ecosystem services they deliver? What are their most frequent ecological interactions?

The Little Things that Run the City project is addressing these and other questions within the boundaries of the City of Melbourne. Here are some of our key findings:

We found that at least 560 insect species occur within the City of Melbourne’s public green spaces. These included species of ants, bees, beetles, cicadas, flies, heteropteran bugs, jumping plant lice, leafhoppers, treehoppers, planthoppers, parasitoid and stinging wasps, and sawflies. The insect group with the highest diversity was beetles, followed by parasitoid wasps and flies.

The most common species was a ‘Minute brown scavenger beetle’ in genus Cortinicara. Minute brown scavenger beetles are tiny and dark, and measure about 2 mm in length. Truly ubiquitous in the City of Melbourne, the species was collected in all studied sites and habitats, and in association with 102 different plant species – that’s 94% of all surveyed plant species!

The European honey bee Apis mellifera was the most common bee species. We also recorded many Australian native bees, including chequered cuckoo, leafcutter, and blue-banded bees.

A blue-banded bee ( Amegilla asserta ) flying towards a black-anther flax-lily.  Image: Luis Mata

A blue-banded bee (Amegilla asserta) flying towards a black-anther flax-lily. Image: Luis Mata

We have recorded at least four new species to science. These include an ant in genus Turneria, a lacebug in genus Tingis, and two jumping plant lice: Mycopsylla sp. nov. and Acanthocasuarina sp. nov..

As many as 97% of all recorded species were native to Australia. The most common non-native species was the Argentine ant Linepithema humile, an aggressive invasive species known to displace native ants and capable of disrupting ant-mediated seed dispersal interactions.

Mid-storey was the habitat type with the highest insect diversity. As many as 337 species were recorded in association with mid-storey plants. The second most diverse habitat type was tree, followed by grassland and lawn.  

The tussock-grass Poa labillardierei was the plant species with the highest associated insect diversity. As many as 103 insect species were associated with this native grass. The native wallaby grass Rytidosperma sp. and kangaroo grass Themeda triandra also had large numbers of associated insect species. The shrub with the highest associated insect diversity was the fragrant saltbush Chenopodium parabolicum, followed by sweet bursaria Bursaria spinosa, gold-dust wattle Acacia acinacea and hop goodenia Goodenia ovata.

There were over 60% more insect species in native than non-native tree species. Interestingly, however, the tree species with the highest associated insect diversity were both the native spotted gum Corymbia maculata and the non-native pepper tree Schinus molle.

We documented approximately 2,200 associations between insect and plant species. On average, each insect species was associated with 3.3 plant species. For example, the most generalist herbivore recorded in the study, a tiny green leafhopper, was recorded in association with 57 plant species, which is more than 50% of all surveyed plant species. This is assuming of course that it actually feeds on every plant species that we found it on!

A dingy swallowtail ( Papilio anactus ) in Carlton Gardens.  Image: Luis Mata

A dingy swallowtail (Papilio anactus) in Carlton Gardens. Image: Luis Mata

Half of all adult insect species recorded in the study were herbivores. Of these, as many as 68% were folivores, a guild in which species specialise to eat leaves.

We don’t know how many species were pollinators! What we do know is that as many as 25% of all recorded species are known to visit flowers to collect nectar and/or pollen – that is almost 150 species of beetles, parasitoid and stinging wasps, flies, heteropteran bugs, ants, and, of course, bees.

Over 40% of all recorded insect species were predators or parasitoids. These species are therefore capable of regulating the populations of potential insect pests.

The insects recorded in the study may supply at least two types of food: honey and lerps. We documented only one species of honey-producing bee, namely the non-native European honey bee. Lerps are crystallised protective structures made out of the sugar-rich liquid honeydew exudated by the immature stages of jumping plant lice.

The Little Things that Run the City project illustrates the importance of insect biodiversity conservation to the City of Melbourne, and by extension, to other cities worldwide. Our findings are being applied to identify where to prioritise conservation activities, guide the design and maintenance of green spaces, and assist decision-makers considering insects in broader biodiversity plans and strategies. The study is providing valuable baseline data that can be integrated into the council’s planned research agendas; for example, in future iterations of the City of Melbourne’s BioBlitz and in the future development of monitoring programs.

Our findings are also providing data to The shared urban habitat, one of the five main research lines of the National Environmental Science Programme – Clean Air and Urban Landscapes Hub, and to the recently awarded Australian Research Council Linkage Project Designing green spaces for biodiversity and human well-being.

Insects are the most diversified animal group on our planet - and in our city! From a functional perspective they are arguably the most important as well. The ‘little things that run the city’ spread seeds, eat rubbish, pollinate food crops and flowers, produce honey, keep soils healthy, help control weeds and pests, and are a food source for some of our other most dear animals, such as lizards, bats and birds. Keeping them safe and healthy within our city should be one of our top urban conservation priorities!


Dr Luis Mata is a postdoctoral researcher at RMIT University’s Interdisciplinary Conservation Science Research Group. You can discover more about Luis and his research on his research blog. 

Banner image of a shield bug from genus Cuspicona courtesy of Luis Mata.