Would you like to participate in our research?
The question is: who opens unripe cactus fruits?
Dr. Sophie Petit has been studying cacti and bats on Curaçao for 24 years. Part of her research in collaboration with Leon Pors and Anna Rojer shows that very few fruits get the opportunity to ripen. Most are eaten unripe when the seeds are not viable – animals eating unripe fruits are thus cactus predators! WHO OPENS THESE UNRIPE FRUITS? Help us find out.
What you will need:
binoculars, pen and paper, the data sheet (click here to download the data sheet, and click here for an example data sheet), access to datu, kadushi, or kadushi di pushi (lucky you if they are in your garden), a bird book, food-water-sunscreen-hat, mat to sit on, a little bit of free time, and it would be great if you had a camera with a telephoto lens (but not mandatory).
Facts to know about fruits:
when the fruits are ripe (5-6 weeks for datu and kadushi), they swell and split open. Datu fruits become very shiny and lose their spines. The “skin” of kadushi fruits becomes very thin in one location, usually at the bottom, before it splits open. Bats can only access the fruits if they have split open; the many small black seeds are then viable and are dispersed by bats. Sometimes datu fruits can become shiny and lose their spines if they have been opened by an animal, so for the purpose of this study, it is very important to make sure that the fruits are not mature ones (use small to intermediate size for a particular cactus). Note that seeds are viable for about a week before fruits open, so it is very important in this study to work on fruits that we are sure are immature.
please sit at least 10 m away from a cactus or group of cacti, with your binoculars. Drawing branches on a piece of paper can help to follow particular fruits. Report vertebrate animal visits to fruits that you can see well. The most IMPORTANT IS TO NOTE WHETHER THE FRUIT IS BEING OPENED BY THE ANIMAL OR WHETHER IT WAS ALREADY OPEN WHEN THE ANIMAL STARTED FEEDING ON THE FRUIT. Note that barika hel sometimes feeds on the sugar secretions on the skin of closed datu fruits. Only record one observation per animal per fruit (e.g. if a fruit is visited by a mofi several times, only make one record). Please use separate data sheets if you are observing two different cactus species at the same time. ONLY REPORT ON SMALL TO MEDIUM FRUITS that are certainly unripe.
Procedure for submitting information:
please fill out the data sheet electronically and return to the Curaçao Footprint Foundation after every field trip (firstname.lastname@example.org). The closing date for this research is 30 September 2013 (but we are always happy to get your interesting information after that date). A summary of the findings will be provided in the newsletter. Note that we may contact you by e-mail if we require additional information.
Please look at the cactus pictures for identification.