WHEN YOUR VERY FIRST MEAL IS YOUR SIBLING
Nature never stops amazing us with the incredible diversity of parental strategies that have evolved to increase offspring survival. During development, mothers provide nutrients to their young in different ways, usually through a placenta, maternal tissues, or yolk stored in the egg. But, can you believe that there is an extreme case in which the food that mothers provide is the siblings that are sharing the same maternal space? This phenomenon, known as adelphophagy, is relatively rare in the animal kingdom, but has been documented in vertebrates such as sharks, as well as in invertebrates like echinoderms, insects, molluscs, and annelids.
Maternal feeding of siblings also occurs in two types of invertebrates that are unfamiliar to many of us: flatworms and ribbon worms. Both are…
IS THE HEALTH OF THE OFFSPRING REALLY ONLY THE MOTHER’S RESPONSIBILITY?
Decades of research have been dedicated to link the mother’s health and nutritional habits with the health of their children in both the short and the long term. And yes, it is important of course! However, what do we know about the effect of the father’s nutritional habits? Is the father’s only job really to contribute sperm to fertilize the egg? In short, the answers are “yes” and “no”. Yes, because the nutritional habits of the father also affect the offspring. And no, because the sperm does not only contribute genetic material, but also play a fundamental role in fetal and child development.
In an elegant review, Skerrett-Byrne and colleagues (2025) remind us that sperm is far from being only a passive DNA carrier, but rather is an epigenetically active player …
AN OVIPAROUS CAECILIAN FEEDS ON OVIDUCTAL MILK
When you think about amphibians, caecilians are probably not the first animals that come to mind. They are among the most poorly understood amphibians, largely due to their fossorial lifestyle. Classified in the order Gymnophiona, they differ from frogs and salamanders because they are limbless and elongated, resembling snakes or worms more than a “typical” amphibian.
Despite their secretive nature, researchers have documented interesting parental feeding mechanisms, such as…
MILK PROVISIONING IN TSETSE FLIES
You probably have heard about the tsetse fly, the African fly which feeds on blood of both humans and animals. They are a troubling public health concern because they are vectors of African trypanosomes. However, tsetse flies are also known for something else - something extraordinary.
Similar to humans, tsetse flies possess milk glands! Mother flies give birth to live young, after larvae develop inside of their uterus. To nourish their larvae …
FEEDING ON SLIME
Velvet worms are among the most extraordinary animals on earth! With a very simple body structure, these ancient animals have been living on our planet for nearly 500 million years. Despite their name, they are not actually worms. They are not insects either, but look like caterpillars, and belong to their own phylum called Onycophora.
Onycophorans have a remarkable technique for hunting. To capture their prey, velvet worms eject a sticky, adhesive slime from their oral papillae, which are located close to their mouth. The sticky slime immobilizes the prey so that the velvet worm can then casually approach it.
In a study of feeding behavior conducted in Costa Rica in 2019, researchers documented for the first time a form of parental feeding in velvet worms...