The seed always knows best: Colin Burrows and the seed predators of Ahuriri Bush

On Friday I attended the funeral of Colin Burrows. Colin was a well known, well regarded, and “formidably well informed” plant ecologist (to borrow David Galloway’s apt phrase from the funeral). He was also a botanist, biogeographer, mountaineer, conservationist, historian, and poet, among other things. And a really nice guy. It’s sad that’s he’s gone.

I had the privilege of being taught by Colin when I was an undergraduate and honours student back in the early 1990s at the University of Canterbury. I was amazed by the extraordinarily depth and breadth of his knowledge of New Zealand plants and vegetation. He was a man of the mountains and knew all of their botanical inhabitants. His lectures and field trips were filled with plants I’d never heard of, which made be feel quite inadequate as I scrambled to catch up. It’s what I expected from university and I enjoyed the challenge.

As something of a tribute to Colin, I thought I’d use my blog post this week to revisit my first scientific paper. It involved Colin’s long standing interest in seeds and my growing interest in plant-insect interactions.

At the end of my honours year of my Bachelor of Science, while I was waiting to head off to Costa Rica for my PhD, Colin organised a small paid project for me. It was to collect and help identify the insects that were eating the seeds of native woody plants in Ahuriri Valley on the Christchurch Port Hills.

Colin had a strong interest in vegetation change (he wrote the text book on the subject) and one of his long running study sites was the Ahuriri Valley. At the time of my research, Colin had projects running on native plant seed production, dispersal, and germination. A hole in his understanding was how many of these seeds were eaten by insects, and by which species.

I spent much of my 1993–1994 summer up in Ahuriri Valley collecting seeds. Our aims for the project were simple: to identify the insect seed predators of many of the common native tree species in Ahuriri Valley, Christchurch Port Hills (and certain other plants of interest), and to get an indication of the percentage of seeds eaten by each predator.

We were fortunate to have entomologist John Dugdale on our team, whose depth and breadth of knowledge of New Zealand insects was (at least) the match of Colin’s plant knowledge. I collected the seeds, recorded the proportions fed on my different insects, and John, for the most part, reared them through to adulthood and figured out what they were.

We wrote up the work as a small paper for the New Zealand Journal of Botany. A colleague at Landcare Research recently, and kindly, referred to it as a “great wee classic”. My biggest lesson from this project, other than that I had a lot to learn, was that there was a vast amount of basic natural history in New Zealand still to be discovered. Being able to put a name on a species was only the beginning. That was about the extent of our knowledge of a great many New Zealand insects. For the most part, it still is.

There are lots of insects mounted on pins in New Zealand museums that were caught as adults, in assorted clever traps, and described for science and given names. For many, perhaps most, of these insects, we still know nothing at all about their larvae and what those eat. Furthermore, insects with larvae that specialise on eating seeds are feeding on the most well defended and usually poisonous parts of a plant. Seeds are plants’ babies, after all, and parents invest a lot in keeping their offspring safe. Seed predator insects (baby plant killers!) typically only have the physiology capable of handling the defences from one species or genus of plant. Because of this, most of our native plants have their own specialist native seed predators (and most exotic weeds have no seed predators at all).

We concluded our paper with “it is our hope that this pilot study will encourage plant scientists and entomologists to take a greater interest in this area of plant-animal interaction in New Zealand.” Since then, entomologist Nicholas Martin has produced his extraordinary Plant-SyNZ database that fills many holes in our knowledge of what insects eat what plants.

Still, here we are 20 years later and it’s fair to say that our understanding of the New Zealand food web, of what species eat what species, is still rudimentary. There is still a vast amount of basic natural history in New Zealand waiting to be discovered. Thankfully, modern technology is now making this much easier (and fun!). You can now join me and lots of other New Zealanders making these discoveries on iNaturalist NZ.

Next time you look at a native (or exotic) plant in seed, have a second look. Are there insects inside? Take some photos and load them on iNaturalist NZ. Better yet, put those seeds in a jar and see what adult insects emerge, and share photos of those adults on iNaturalist NZ. Someone probably already knows the name of the adult, but we may not yet know what their larvae eat. The paper that Colin, John, and I wrote is still just the beginning.

Here’s the link to our paper.

Sullivan, J. J., Burrows, C. J., and Dugdale, J. S. 1995. Insect predation of seeds of native New Zealand woody plants in some central South Island localities. New Zealand Journal of Botany, 33:355–364. dx.doi.org/10.1080/0028825X.1995.10412962

And, in honour of Colin, here’s a selection of his classic papers on seeds and Banks Peninsula/Port Hills plants (some of which are currently hard to find on Google).

Burrows, C.J. 1973. The ecological niches of Leptospermum scoparium and L. ericoides (Angiospermae: Myrtaceae) New Zealand Natural Sciences (Mauri Ora), 1:5-12 www.science.canterbury.ac.nz/nzns/issues/vol1-1973/burrows.pdf

Burrows, C.J. 1989. Patterns of delayed germination in seeds. New Zealand Natural Sciences 16:13-19 www.science.canterbury.ac.nz/nzns/issues/vol16-1989/burrows.pdf

Burrows, C. J. 1994. The seed always knows best. New Zealand Journal of Botany, 32(3):349–363. dx.doi.org/10.1080/0028825X.1994.10410478

Burrows, C. J. 1994. Fruit, seeds, birds and the forests of Banks Peninsula. New Zealand Natural Sciences, 21:87–108.www.science.canterbury.ac.nz/nzns/issues/vol21-1994/burrows.pdf

Burrows, C. J. 1994. Fruit types and seed dispersal modes of woody plants in Ahuriri Summit Bush, Port Hills, western Banks Peninsula, Canterbury, New Zealand. New Zealand Journal of Botany, 32(2):169–181. dx.doi.org/10.1080/0028825X.1994.10410366

Burrows, C. J. 1994. Seed trapping in Ahuriri Summit Bush Scenic Reserve, Port Hills, western Banks Peninsula, 1985–1986. New Zealand Journal of Botany, 32(2):183-215 dx.doi.org/10.1080/0028825X.1994.10410367

Burrows, C. J. 1995. Germination behaviour of the seeds of six New Zealand woody plant species. New Zealand Journal of Botany, 33(3):365-377 dx.doi.org/10.1080/0028825X.1995.10412963

Burrows, C. J. 1995. Germination behaviour of the seeds of the New Zealand species Aristotelia serrata, Coprosma robusta, Cordyline australis, Myrtus obcordata, and Schefflera digitata. New Zealand Journal of Botany, 33(2):257-264 dx.doi.org/10.1080/0028825X.1995.10410488

Burrows, C. J. 1995. Germination behaviour of seeds of the New Zealand species Fuchsia excorticata, >Griselinia littoralis, Macropiper excelsum, and Melicytus ramiflorus. New Zealand Journal of Botany, 33(1):131-140 dx.doi.org/10.1080/0028825X.1995.10412950

Burrows, C. J. 1996. Germination behaviour of the seeds of seven New Zealand vine species. New Zealand Journal of Botany, 34(1):93-102 dx.doi.org/10.1080/0028825X.1996.10412696

Burrows, C. J. 1996. Germination behaviour of seeds of the New Zealand woody species Melicope simplex, Myoporum laetum, Myrsine divaricata, and Urtica ferox. New Zealand Journal of Botany, 34(2):205-213 dx.doi.org/10.1080/0028825X.1996.10410685

Burrows, C. J. 1996. Germination behaviour of seeds of the New Zealand woody species Ascarina lucida, Coprosma grandifolia, Melicytus lanceolatus, and Solanum laciniatum. New Zealand Journal of Botany, 34(4):509-515 dx.doi.org/10.1080/0028825X.1996.10410131

Burrows, C. J. 1996. Germination behaviour of seeds of the New Zealand woody species Coprosma foetidissima, Freycinetia baueriana, Hoheria angustifolia, and Myrsine australis. New Zealand Journal of Botany, 34(4):499-508 dx.doi.org/10.1080/0028825X.1996.10410130

Burrows, C. J. 1996. Germination behaviour of seeds of the New Zealand woody species Alectryon excelsus, Corynocarpus laevigatus, and Kunzea ericoides. New Zealand Journal of Botany, 34(4):489-498 dx.doi.org/10.1080/0028825X.1996.10410129

Burrows, C. J. 1996. Germination behaviour of the seeds of seven New Zealand woody plant species. New Zealand Journal of Botany, 34(3):355-367 dx.doi.org/10.1080/0028825X.1996.10410700

Burrows, C. J. 1995. Germination behaviour of the seeds of four New Zealand species of Coriaria (Coriariaceae). New Zealand Journal of Botany, 33(2):265-275 dx.doi.org/10.1080/0028825X.1995.10410489

Burrows, C.J. 1997. Reproductive ecology of New Zealand forests. 1. Natural seed storage phenomena. New Zealand Natural Sciences, 23: 31-52 www.science.canterbury.ac.nz/nzns/issues/vol23-1997/burrows_a.pdf

Burrows, C.J. 1997. Reproductive ecology of New Zealand forests. 2. Germination behaviour of seeds in varied conditions. 23:53-69 www.science.canterbury.ac.nz/nzns/issues/vol23-1997/burrows_b.pdf

Burrows, C. J. 1999. Germination behaviour of seeds of the New Zealand woody species Alseuosmia macrophylla, A. pusilla, Cordyline banksii, Geniostoma rupestre, Myrtus bullata, and Solanum aviculare. New Zealand Journal of Botany, 37(2):277-287 dx.doi.org/10.1080/0028825X.1999.9512634

Burrows, C. J. 1999. Germination behaviour of seeds of the New Zealand woody species Beilschmiedia tawa, Dysoxylum spectabile, Griselinia lucida, and Weinmannia racemosa. New Zealand Journal of Botany, 37(1):95-105 dx.doi.org/10.1080/0028825X.1999.9512616

Genet, R. & Burrows, C.J. 1999. The ecological restoration of Otamahua/Quail Island. 1. The island’s physical setting and history, and planning for ecological restoration. New Zealand Natural Sciences, 24:113-125 www.science.canterbury.ac.nz/nzns/issues/vol24-1999/genet.pdf

Burrows, C.J., Wilson, H.D. & Meurk, C.D. 1999. The ecological restoration of Otamahua/Quail Island. 2. The vascular land flora and vegetation. New Zealand Natural Sciences, 24:127-150 www.science.canterbury.ac.nz/nzns/issues/vol24-1999/burrows.pdf

Burrows, C.J. & Watson, J.K. 2000. The ecological restoration of Otamahua/Quail Island. 3. Problem plants and their control. New Zealand Natural Sciences, 25:11-32 www.science.canterbury.ac.nz/nzns/issues/vol25-2000/burrows.pdf

Burrows, C.J. & Leckie, A. 2001. The ecological restoration of Otamahua/Quail Island. 4. The indigenous woodland plantings 1998-2001. New Zealand Natural Sciences, 26:33-65 www.science.canterbury.ac.nz/nzns/issues/vol26-2001/burrows.pdf

Burrows, C.J. 2002. The ecological restoration of Otamahua/Quail Island. 5. Progress with shrub weed control. New Zealand Natural Sciences, 27:27-39 www.science.canterbury.ac.nz/nzns/issues/vol27-2002/burrows.pdf