Posted by Delayn Fritz @WildOptic

Progress and technological advancement allows us the brilliant capability to receive goods from the other side of the planet in only a matter of days. This is a good thing for the delivery men who just 100 years ago would have had to suffer an arduous journey just for the yearly supply of salt. However, this decrease in vectoring time has meant that survivorship of stowaway critters has increased, as well as an overall increase in the amount of trade volume. In fact, it has been shown that the amount of trade may be the biggest indicator of how many invasive species are established in a given country, and this trade has steadily been increasing.

So this may leave you wondering how do species become invasive, and move from the initial ’transport stage’ and proliferate into an invasive species. A unified framework for this process has been widely accepted and explains several stages from transportation, to establishment, to spread. This is important because between each stage are biological barriers that may inhibit species from moving to the next stage. Species can overcome these barriers, through increased propagule pressure (i.e. the amount of individuals being introduced), by being pre-adapted to the climate of the new environment, and perhaps by possessing certain biological characteristics.

The unified framework proposed by Blackburn et al. 2011

Why should we care about the process and not just focus on eradication? The associated effort and cost to remove a species increases as it occupies more area. The fruit fly incursion responses in 2012 and 2014 both cost around $2 million, and that was just the size of a suburb. The real goal and money saver while getting the best results would be to prevent a species from establishing and/or spreading in the first place, this is best done in conjunction with understanding the invasion pathway and bolstering the natural barriers that already exist.

The invasion curve refined by Harvey and Mazzotti

This is where my MSc project comes in. I am studying a data set spanning 60 years of interception data at the border, and records of spread within New Zealand to try and understand the reasons that non-native ant species have either been successful in establishing and spreading or why they have failed. In starting to really understand how these barriers affect success of species we can improve chances of successful prevention through risk assessment.

Nylanderia spp. in the urban garden (Image credit: Delayn Fritz)

 Delayn Fritz is an MSc student in the Centre of Biodiversity  and Biosecurity, School of Biological Sciences, University of Auckland. He is interested in the invasion process of ants (Hymenoptera: Formicidae) in New Zealand. He is supervised by Darren Ward and Eckehard Brockerhoff (Scion, B3).

Posted by Ellery McNaughton @EJ_McNaughton

Some birds don’t seem to care that dawn frequently looks nicer than it feels

I struggled in achieving the Herculean feat of getting up before dawn today. Fortunately for me, I had help – my local tūī (Prosthemadera novaeseelandiae) decided to serenade the neighbourhood, a sound far more pleasant than the alarm on my phone. Not everyone is so appreciative, especially when the ‘dawn chorus’ begins well before its name would suggest.

Timing of dawn song is influenced by a number of natural factors. For example, studies have shown that rain, noise from nocturnal insects, intensity of moonlight, and even individual personality can advance or delay the onset of dawn song. Of course, factors such as noise and light intensity can also be introduced into the environment as a result of human impact and urbanisation.

The onset of dawn song has been found to be much earlier for urban birds than for their rural counterparts, a difference attributable to traffic noise and artificial light at night (ALAN).

Snooze button nowhere to be found. Photo credit: Tony Wills

Urban birds have been found to sing earlier in the morning when exposed to traffic noise. And it’s not just road vehicles – birds near airports also advance their singing to avoid peak aircraft traffic in the morning. ALAN has also been linked to advancing morning bird song. There are many sources of urban ALAN, but a large proportion comes from streetlights. The effects of different types of streetlights on the timing of urban bird song is not yet fully understood, although there have been some indications that different technologies can have varying effects on different species.

This is the area that I’m interested in for my research. I hope to determine whether changing the streetlights from orange (high-pressure sodium) lights to white (light emitting diode) lights makes my local alarm clock start serenading earlier or later in the morning. Coincidentally, I am also forever grateful to the inventors of audio recorders for enabling bleary-eyed ecologists to sleep through their data collection.

Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her project will investigate the effects of a city-wide changeover in streetlight technology on urban bird behaviour and ecosystem function. She is supervised by Margaret Stanley, Jacqueline Beggs, Kevin Gaston(University of Exeter, UK) and Darryl Jones (Griffith University, Australia).

Did you know that there are 27 species of native bees in New Zealand that are found nowhere else in the world? If your answer to this question was ‘no’, don’t worry – you are not alone! While most people are familiar with the ‘honey bee’ and ‘bumblebees’ (species that have been purposefully introduced to New Zealand to improve the pollination of crops), native bees often go unnoticed.

Most native bees in New Zealand are solitary and nest in the ground. All native bees consume pollen and nectar, and have similar life cycles. Female bees construct the nests in which their young are raised by digging blind-tunnels in the soil or using pre-existing tunnels in plant material. Each nest contains a cell in which the female bees place all the food that their larvae will need. They then deposit an egg and seal the cell to avoid contact with that part of the nest until the new bee has developed. Male bees on the other hand spend most their time feeding, mating and resting.

Native ground-nesting bees mating (photo by Anna Kokeny).

During the active flight season (mid-spring to early autumn), thousands of individuals nest alongside each other, forming large communities. By the end of autumn, adult bees die but the larvae overwinter until they emerge in mid-spring and the cycle repeats!

Native ground-nesting bee emerging from its nest (photo by Anna Kokeny).

Studying native bees can be difficult as there are few ways to easily monitor them. As a result, there is much to learn about their populations, diversity and distribution throughout New Zealand. The aim of my master’s project is to investigate how soil characteristics influence the distribution of solitary-ground nesting bees in the Waikato and Northland region. In order to do this, I am analysing soil samples collected from sites with native bees and sites without native bees and comparing this to the abundance and diversity of native bees. Already, my summer sampling has revealed that the most common species of native bee within those regions are Leioproctus paahaumaa and L. imitatus.

Collecting soil sample from a native bee nest site using a soil corer (photo by Anna Kokeny).

The two most frequently asked questions I’ve encountered whilst collecting data were: “do they make honey?” and “do they sting?” No, native bees do not produce honey and will very rarely sting humans. So, why should we care about them? Native bees are key pollinators of New Zealand’s native flora. They are known to pollinate a wide range of plants including mānuka, kānuka and pohutukawa.

Native ground-nesting bee laden with pohutukawa pollen (background yellow colour)(photo by Anna Kokeny).

Native bee foraging on manuka flower (photo by Anna Kokeny).

Also, surprisingly Leioproctus bees can open a mistletoe flower (Peraxilla tetrapetala) by biting the tip of the bud. The main pollinators of mistletoe are bellbirds and tūī, but since introduced pests have significantly reduced bird numbers, native bees have partially replaced them as pollinators (Robertson et al., 2005).

 Get involved

To find out more about native bees join this Facebook group. This page is dedicated to NZ native bees – what they look like, where they live, what they do and how we can support them.

Anna Kokeny is a MSc student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is interested in the distribution of native solitary ground nesting bees in the Waikato and Northland regions. She is supervised by Jacqueline Beggs, Jamie Stavert, Anne Gaskett and David Pattermore (Plant and Food Research).