Two recent stories advise us to help monarchs by NOT doing what is temporarily pleasing. I consider these warnings emblematic of the conservation actions people should be taking in general, for more than monarch butterflies. We’ve developed a cultural repertoire of self-ennobling gestures that allow us to think we are Saving The World. When their significance is evaluated realistically, however, these gestures are more feel-good activities (like recycling plastic*) than game-changers. Conservation isn’t planting fancy exotic flowers and calling it pollinator habitat. It’s not small projects framing individual people as saviors of individual butterflies they name and photograph for Instagram. Monarch conservation, like the problem of plastic waste, requires large coordinated efforts focused on the causes. For monarchs, we need to address needs across the spectrum of habitats comprising their breeding and overwintering territories.
science mag — Monarchs that ‘drop out’ of the migration game pick up more parasites
In recent years, more people in the US have planted tropical milkweed strains that don’t die back in the fall. Scientists warned that these plants could be disruptive to migration because milkweed senescence is one of the triggers for monarchs to migrate (along with cooler temperatures, changes in day length, and the sun’s angle). Monarch biologists advised people growing tropical milkweed to cut it to the ground in fall and keep it from regrowing to prevent out-of-season egg laying. But this hasn’t happened large-scale because people like tropical milkweed flowers.
Due to out-of-season milkweed availability and warming winter temperatures, some monarchs have established year-round non-migratory populations in southern areas of the US. Diseases are a main threat to these non-migratory populations. Among migratory monarchs, diseased butterflies die and drop out as the population flies onward, which helps limit disease spread. Resident populations don’t fly away from the diseased dying butterflies.
To learn more about how resident monarch populations affect the migratory monarchs, scientists captured and analyzed traveling butterflies for signs of disease during spring and fall migrations in 2014 and 2015.
The researchers worked with citizen scientists to examine more than 500 monarchs from nine different sites in Texas, half of which had resident colonies, and half of which were exclusively pit stops for migratory monarchs. Migratory monarchs that stopped at resident sites were 13 times more likely to be infected by parasites and three times more likely to reproduce outside of the normal breeding season compared with other migrants….
This doesn’t necessarily mean the migrants at these sites became infected by mixing with residents. The scientists say butterflies that are already infected might simply drop out of the migration at the first sign of milkweed plants—often the tropical strains that host the resident colonies. Sensing the maturity of the tropical milkweed might also cause a biological change in the butterflies, telling them to cut their migration short to mate early, a ritual they usually put off until after the springtime migration north is completed.
Based on these findings and other research, biologists encourage people to plant only milkweed species native to their area and to eliminate tropical milkweed. Native plants and monarchs change with the seasons, and the synchrony of their changes is important to monarch population recovery.
source
The Daily Bucket is a nature refuge. We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns spinning around us.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
|
Xerces Society — Keep Monarchs Wild! Why captive rearing isn’t the way to help monarchs
Captive breeding of monarchs (eggs laid in captivity then distributed to other areas for rearing and wild release) has been criticized due to the associated high levels of diseases and other health troubles. But captive rearing of wild-laid eggs is such a popular endeavor that a subculture has developed around this activity by people who see themselves as Butterfly Saviors. Xerces finally has released a statement opposing this practice.
In an attempt boost the population people are turning to large-scale captive rearing of wild-collected monarchs. Captive rearing is the practice of collecting eggs, caterpillars, or pupae (chrysalises) from the wild, raising them in captivity, and then releasing them. [...]
The practice has now become so commonplace in some circles, however, that hundreds or even thousands of monarchs are reared and released by a single individual each year. Many individuals with good intentions adopt this practice under the assumption that they are helping monarchs by lowering the butterfly’s notoriously high predation and parasitism rates found in the wild, where less than 10% of eggs make it to adulthood. By that logic, the more monarchs they rear, the more monarchs will make it to Mexico or California come winter. On the surface, this sounds like a good thing, but if you dig a little deeper, you’ll see this practice does not match up with what we know about how to actually reverse the monarch’s decline. There are no studies or other compelling evidence that show that releasing captive reared monarchs boosts the population. And if, at the heart of it, we are really trying to help monarchs, then we need to carefully examine the risks of captive rearing.
Xerces goes on to explain why captive rearing doesn’t help monarch populations.
Monarchs evolved with high rates of predation and parasitism. Human intervention intended to ensure a higher proportion of eggs survive to adulthood might not be best for the population, even if your garden has more individual monarchs as a result. The point of conservation is to support the wild population as a whole.
Synchrony of butterflies and their resources (milkweed host and nectar plants) is part of the population dynamics in an ecosystem. Someone might collect wild-laid eggs, rear larvae to adults indoors, and release 100 monarchs where only 8 of the eggs would have naturally survived to adulthood. This abundance can create an unnatural situation that carries over into subsequent generations.
- Increased Risk of Disease
Captive rearing of monarchs occurs in unnatural settings. People use screened boxes and other enclosures containing milkweed leaves. This results in greater monarch densities than occur in the wild where only a few eggs are laid on a plant. The higher density makes the animals more prone to diseases. Some people who captive rear are careful about OE, a protozoan disease, and know how to test adults for OE. But other pathogens that aren’t as well studied also make monarchs sick.
People can rear a few monarchs for the delight of school students or as an uplifting personal moment. You don’t need to deny yourself the thrill of raising a monarch. This article concludes with the Xerces guidelines defining how many monarchs to rear in captivity and how best to do so safely.
What we should be doing instead of captive rearing isn’t a cute Instagram photo but if we all work together, we can be effective. Xerces points out that we need to take steps that “address the reasons the species is in trouble to begin with.”
- Protect and enhance natural habitat by planting native nectar plants and appropriate milkweed species for our area. Get rid of tropical milkweed.
- Avoid pesticide use.
- Support local agriculture that uses organic, wildlife-friendly cultivation measures.
- Engage in ethical citizen science.
- Advocate for policy changes that benefit monarchs and other wildlife.
These actions are less charming than captive rearing, but more meaningful if we remain dedicated. We focus on long term gains instead of the momentary pleasure of watching a hundred butterflies we raised from eggs fly away, one by one. We relinquish our role as individual saviors of individual monarch butterflies and engage in collective efforts. The Instagram photos for this type of conservation are images taken years apart showing before and after views of restored landscapes. Through united action, we might experience the enduring pleasure of saving the North American monarch butterfly population.
source
SPOTLIGHT ON GREEN NEWS & VIEWS
EVERY SATURDAY AT 3 P.M. PACIFIC TIME
DON’T FORGET TO VIEW METEOR BLADE’S COLLECTION OF LINKS AND EXCERPTS FROM ENVIRONMENTALLY ORIENTED POSTS PUBLISHED ON DAILY KOS DURING THE PREVIOUS WEEK
|
* More Recycling Won't Solve Plastic Pollution
Recycling plastic is to saving the Earth what hammering a nail is to halting a falling skyscraper. You struggle to find a place to do it and feel pleased when you succeed. But your effort is wholly inadequate and distracts from the real problem of why the building is collapsing in the first place.
