New paper: Cheater or mutualist? Novel florivory interaction between nectar-rich Crotalaria cunninghamii and small mammals

Authors: Tony J. Popic, Yvonne C. Davila and Glenda M. Wardle

Published in: Austral Ecology 

Abstract:

Animals visit flowers to access resources and by moving pollen to conspecific individuals act as pollinators. While biotic pollinators can increase the seed set of plants, other flower visitors can reduce seed set directly by damaging vital reproductive organs and indirectly by affecting the way the plant interacts with subsequent flower visitors. It is, therefore, vital to understand the varied effects of all visitors and not only pollinators on plant fitness, including those visitors that are temporally or spatially rare. We document the first known case of flower visitation by small mammals to Crotalaria cunninghamii (Fabaceae), a plant species morphologically suited to bird pollination. 

crotalaria yd 2

Crotalaria cunninghamii (Fabaceae) flowering, Simpson Desert (photo by Yvonne Davila)

During a rain-driven resource pulse in the Simpson Desert in 2011, the rodents Mus musculus (Muridae) and Pseudomys hermannsburgensis (Muridae) visited flowers to remove nectar by puncturing the calyx. We investigated the effects of this novel interaction on the reproductive output of C. cunninghamii.

sandy inland mouse yd

Sandy inland mouse, Pseudomys hermannsburgensis (Muridae) (photo by Yvonne Davila)

Compared with another recent resource pulse in 2007, plants flowering during mammal visitation had five times as many inflorescences per plant, 90% more flowers per inflorescence, and two to three times more nectar per flower, but this nectar was 30% less sugar rich.

Nectar readings on Crotalaria

Here I am using a refractometer to measure nectar sugar content from Crotalaria cunninghamii flowers (photo by Glenda Wardle).

Concurrently, rodent plagues were up to three times larger during this rain-driven resource pulse than during a previous pulse in 2007. Up to 75% of flowers had evidence of small mammal florivory, but this was not necessarily destructive, as up to 90% of fruit had the remains of florivory. Through a series of exclusion experiments, we found that small mammal florivory did not directly reduce seed set. We conclude that rain-driven resource pulses led to a unique combination of events that facilitated the novel florivory interaction. Our findings emphasize the dynamic nature of biotic interactions and the importance of testing the role of all visitors to pollination services.

raining on dune 2

Rain in the Simpson Desert in 2011 (photo by Yvonne Davila)

Reference: Popic, T. J., Davila, Y. C. and Wardle, G. M. (2015), Cheater or mutualist? Novel florivory interaction between nectar-rich Crotalaria cunninghamii and small mammals. Austral Ecology. doi: 10.1111/aec.12324

Article Link: http://onlinelibrary.wiley.com/doi/10.1111/aec.12324/abstract

 

 

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ACSME14 conference poster – Approaches to study and conceptions of biology

Approaches to study and conceptions of biology: differential outcomes for generalist and vocational degree students

On 29th September to 1st October 2014, the Australian Conference for Science and Mathematics Education (ACSME) was held at The University of Sydney and University of Technology Sydney. The 2014 conference theme was Student engagement: from the classroom to the workplace. I collaborated with Rosanne Quinnell, Elizabeth May and Mary Peat (The University of Sydney) on this presentation.

Interest in the subject (extrinsic versus intrinsic) and intention of study (e.g. attaining qualification, training for career, broadening horizons) can influence students’ approaches to learning. Our goal is to deliver a first year biology curriculum that is both (1) deep and engaging for those intrinsically interested and continuing in biology, and (2) broad and relevant for students enrolled in vocational degrees.

We evaluated our learner profiling method (Quinnell et al. 2012) as a means to inform our first year biology curriculum design, which must be suitable for our diverse cohort of students across a broad range of degree programs, i.e. generalist and vocational degrees.

Questions:

  1. How do students’ approaches to learning (Learner Profile) change over the semester?
  2. Do students enrolled in vocational (professional) degrees engage with our curriculum differently from students enrolled in generalist degrees?

Findings:

1.Students’ parameters change significantly from the beginning to the end of the first semester (Table 1, Fig. 2, poster).

2.Students enrolled in generalist degrees (56% of entire cohort) demonstrated greater engagement with our biology curriculum than those enrolled in vocational degrees (Fig. 2, poster).

3.Our data provide some evidence that our curriculum: a) supports generalist degree students whose conception of biology is sound and whose study approach is intrinsic; b) is less than ideal for meeting the needs of students in vocational degrees who do not have deep approaches to learning; and c) has failed to engage students who demonstrated dissonance at the start of semester (Fig. 2, poster).

Our findings suggest that a course in biology literacy would be more suitable to students in vocational degrees and a course that is biology content-rich would suit our generalist degree students.

ACSME14 Quinnell et al

Download a copy of our poster here: ACSME14 poster pdf

Published conference proceedings (extended abstract) available here: ACSME 14 abstract

To cite this work:

Quinnell R, May EL, Peat M, Davila YC (2014) Approaches to study and conceptions of biology: Differential outcomes for generalist and vocational degree students. (Extended Abstract) Proceedings of the Australian Conference on Science and Mathematics Education, University of Sydney and University of Technology Sydney, Sept 29th to Oct 1st, 2014, page 76-77, ISBN Number 978-0-9871834-3-9. <http://openjournals.library.usyd.edu.au/index.php/IISME/article/viewFile/7687/8041&gt;

Related reading:

Quinnell, R., May, E., & Peat, M. (2012). Conceptions of Biology and Approaches to Learning of First Year Biology Students: Introducing a technique for tracking changes in learner profiles over time. International Journal of Science Education, 34(7), 1053-1074.

Quinnell, R., May, E., Peat, M., & Taylor, C. (2005). Creating a reliable instrument to assess students’ conceptions of studying biology at tertiary level. Proceedings of the Uniserve Science Conference: Blended Learning in Science Teaching and Learning, 30 September 2005 (pp. 87-92) Sydney: Uniserve Science, The University of Sydney. http://science.uniserve.edu.au/pubs/procs/wshop10/2005Quinnell.pdf