Arxiu d'etiquetes: butterflies

18 essential mobile applications for field trips

Gone are the days when we had to carry guides and guides to enjoy identification of species in the sea or field. Despite the nostalgia of those printed guides, today, thanks to mobile applications, any nature lover can carry in a pocket all kind of information.

As a lover of nature or biology, do not miss these 18 applications to identify and learn from everything around you. Do you need more than 18? Don’t miss part two.



We start with a highlight: this wonderful application lets you know what wildlife is around you anywhere in the world. Setting on a map our location, the app will indicate us  which species can be found in the area where we are classified by groups (birds, amphibians, insects, trees, plants, fish…) in a database of more than 900,000 species.

In addition to the description, pictures, etc, of the species, we can mark if we have done any sightings, helping to provide data on the frequency of appearance of the species and having a record of our  own observations.

We can also find species directly from the browser or search field.

Available in google play market Available an APP store


Bioguide allows us to have in our Android mammals, birds, reptiles, amphibians, fish, butterflies, moths, plants and mushrooms. When you open the app, it gives you the chance to choose which data download from a total of 100,000 photos and 1,000 sounds. This allows you to use them later offline in nature.

You can search by color, region, name, diet, type of flowering … Within the tab of each species, we will find all kinds of features such as habitat, conservation status, diet, locomotion, systematics, morphology and physiology, trails, similar species… a complete app to keep in mind.


This application allows us to upload photos of our observations (animals, plants, lichens or rocks) to a database of georeferenced photographs. The species will be identified and you’ll be able to save your picture with the correct name. We will also contribute to help in the understanding of biodiversity and conservation of the environment.

Available in google play market  Available an APP store


iNaturalist is another application that will allow us to raise our observations to the database Global Biodiversity Information Facility, to contribute to a better understanding of biodiversity providing data to scientists.

It is a citizen science project where you can start your own project or join one that has already started, contact the experts who identify the species you see and expand your knowledge exchanging experiences with other naturalists.

Available in google play market  Available an APP store


How it is called the mountain in front of you? Just point your mobile towards it and you’ll know the name of the peak anywhere in the world, since its database has 250,000 references. The application has a cost of 3.39 € and works offline.


 Available in google play market


If you are looking for a free alternative,  Geodetic Points will inform you about the name, altitude and how far it is the peak are you looking at . It must be installed with the augmented reality app Layar and only reports on Spanish peaks.


Available in google play market



This is a guide to wild trees of the Iberian Peninsula and Balearic Islands.

arbol capture app

In the guided search, you can describe as in a dichotomous key how the tree is until you reach its species. Then you’ll get a description of it, photographs and distribution. There is also the open search, where from the location, leaves, fruits, flowers and other features the app will guide you to the desired tree. It also has a glossary with more than 80 words and does not require internet connection to use it.

Disponible en google play market

Disponible an APP store

If you need a field guide to trees in Europe and North America, you can try iKnow Trees 2 LITE, with a database of more than 200 species (Android only).


The “Shazam” of plants. Upload up to 4 photos of the plant you want to identify, indicate whether if it is a flower, fruit, stem… and the application will search among more than 4,000 species registered and show you what plant it is. If it is not in the database, you can register it for the rest of the community to identify it.


 Available in google play market

 Available an APP store


Application for identifying mushrooms with 250 species in its free version. In addition to information on the mushroom and possible toxicity of the species, in the thescription we will find the most common mistakes included, to avoid unnecessary collection of species allowing them to continue fulfilling their role in nature. The application allows working offline if you have previously downloaded the libraries with the data.


In the Pro version (6.99 €), we can save the GPS location of the mushrooms that we have found. If a species is not referenced, we can add it to the database.
Available in google play market



If you love ornithology dot not miss this app developed by SEO Birdlife. It is divided into two sections:

  • The bird guide itself , with sheets of the 563 species of birds which are present or have been cited in Spain. In each sheet you will find the layout, drawings, photos, videos, songs and a brief description as well as the months of sighting.

  • Ornithological Itineraries: informs us of the areas of Spain where we can make our observations, with information about the ecological importance of the area and which birds can we find. Spain2 birds

    Available in google play market


    SEO Birdlife also has specific app Water birds to computerize census, identify wetlands closest to our location and view photos and current census of each wetland.

    Available in google play market Available an APP store


    These three apps offer similar functions. We can consider Warbl the “Shazam” of birds. With just recording the song of a bird, the app will recognize it and it will give us information on the bird species without being connected to the network. Warbl can identify 220 UK birds. It has a cost of 5.29 €.


    Available in google play market

    Disponible an APP store

    Field Guide birds Twigle (for iPhone) is another app that not only allows us to identify birds by their song, as Warbl, but allows  us to upload photos of any bird that we sighted and it will recognize the species from our image. It identifies species in North America, Ireland, UK and South Africa.

    Available an APP store

    If you do not have iPhone, Merlin Bird Id in its web version also allows you to recognize a photo from hundreds of species of birds in North America. It also has an application in Android and iOS for identifying birds from a few simple questions.


    If you’re a fan of insects, with this application you can identify insect orders from Australia. If you do not live in Astralia, still it is a good way to learn to distinguish the characteristics that define each order, also present in your country.

     Available google play market  Available an APP store

    iFelix – WOLF

    The field notebooks by emblematic Felix Rodriguez de la Fuente revisited. If you’re a fan of wolves, with this app (€ 2.20) you will have illustrations, 3D animations, photographs, dynamic maps, sounds, utilities (camera geolocation sightings and others) and an area to practice field drawings . Ifelix wolf

    For the moment it is only available the notebook of the wolf, but they are preparing the notebooks of the imperial eagle and the Iberian lynx .

     Available in google play market Disponible an APP store


    Although the description of this application (available only in Android) indicates that it is aimed at children, the truth is that we will find a lot of information about hundreds of animal species. Curiosities, distribution, habitat, behavior, food …

    It also has specific sections for endangered and even extinct species.

     Available in google play market Available an APP store
    This is the selection of All You Need is  Biology of mobile apps touse in the field. In future articles we will complete the list with more applications like maps, compasses and other essential utilities for any naturalist. We eill also discover other applications related to biology.

    Do you know other applications to complete this list? Add it in the comments below!



    • Cover photo
    • All other photographs, unless otherwise indicated, obtained from the corresponding stores .

Why do insects metamorphose?

Most of insects undergo some kind of transformation process during their life cycle in order to reach adulthood -also known as imago phase- (e.g. butterflies). This process is named metamorphosis, although its essence is far from that of metamorphosis performed by amphibians. But, have you not ever wondered why they do this transformation? Which are the sense and the origin of the metamorphosis of insects?

Learn more about the different types of metamorphosis, the origin and sense of these transformations through this article.

Metamorphosis: what is that?

Metamorphosis of the Old World swallowtail (Papilio machaon) (Picture by Jens Stolt).

Metamorphosis is a biological process by which animals develop after birth involving huge transformations and/or anatomical restructurations (both physiological and anatomical) until reaching adulthood.

There are different groups of animals that develop by this process, however most of them don’t share the origin nor the nature of these transformations. Thus, while amphibian metamorphosis takes place by reorganization of youth preexistent organs, in insects it takes place a breaking of tissues and also the appearance of totally new cell clusters.

Ecdysis or molting

First of all, we must talk about molt in order to comprehend the metamorphosis of insects. What means molting? And why is it an essential process for insects and arthropods as a whole?

Every single animal regenerates its external tissues in some way, i.e., those tissues that are in contact with the environment and that protect the organism from external pressures. E.g. mammals regenerate their epidermal tissues periodically; a lot of reptiles shed off their skin frequently; but, what’s about arthropods?

Arthropods, which include the hexapods (group in which we can find all insects), are externally covered by a more or less hard exoskeleton. In contrast with other external animal tissues, the exoskeleton doesn’t detach progressively, and its lack of elasticity restricts the organism growth. So, this element becomes a barrier that limits their size while growing, and is for this that they have to break it and leave it away in order to keep on growing. This kind of molting is known as ecdysis, which is typical of ecdysozoa (arthropods and nematoda).

Take a look at this video of a cicada molting!:

Do all hexapods metamorphose?

The answer is NO. However, it’s necessary to go deeper into the explanation.

All hexapods molt in order to grow, but not all them undergo radical changes to reach adulthood (when they become able to breed). Thus, we can split hexapods into two main groups:


This group includes those hexapods traditionally known as Apterygota or wingless hexapods (Non insect hexapods –proturans, diplurans and colembolas- and wingless insects as Zygentoma or also known as Thysanura –e.g. silverfishes or Lepisma-) and Pterygota or winged insects that have suffered a secondary loss of their wings.

Specimen of Ctenolepisma lineata (Zygentoma) (Wikimedia Commons).

Since they have no wings at any moment of their life cycle, the youth phases of this kind of hexapods almost have no differences from the adult ones. Thus, the youth development is simple and they don’t undergo huge changes to acquire the adult physique; that is, there is no metamorphosis at any point of their life cycle. This kind of development is also known as direct development.

Direct development or ametabolous development (Picture from

Ametabolous hexapods can molt tens of times throughout their development (e.g. 50 times in silverfishes, more or less), even when they become sexually mature.


This group includes Pterygota insects or winged insects (except for the ones that have secondarily lost their wings).

Specimen of Sympetrum flaveolum (Picture by André Karwath)

In contrast of the ones which have been explained above, the youth phases of metamorphic insects are very different from the adult ones; so, after several successive molts they undergo their last change, through which it emerges a winged adult able to breed. After reaching this phase, these insects become unable to molt again.

Types of metamorphosis in insects

So, only Pterygota insects undergo a truly metamorphosis, thanks to which they become winged insects and also reach sexual maturity. But not all these insects perform the same kind of change.

There exist two main types of metamorphosis: the hemimetabolous one (simple or incomplete) and the holometabolous one (complex or complete). Which are their differences?

Hemimetabolous metamorphosis

In the simple, incomplete or hemimetabolous metamorphosis, young insects go through several successive molts until reaching adulthood (or imaginal) stage without going through a stage of inactivity (pupa) and/or stop feeding.

Just after hatching, we referred the newborn as a nymph, which resembles a little to the adult ones (but still not having wings nor sexual organs). Usually, nymphal phases and the adult ones don’t share feed sources nor habitat, so they occupy different ecological niches; in fact, most nymphs have aquatic habits and they go to live on land after reaching maturity (e.g. mayflies).

Adult specimen of the species of mayfly Ephemera danica (Imagen de Marcel Karssies).

In this kind of metamorphosis, nymphs go through some successive molts thanks to which wings are gradually formed and their organism becomes bigger. Finally, nymphs perform their last molt, after which the adult emerges: a winged organism that is able to breed.

Take a look to this scheme that sums up this process:

______Hemimetabolous development of a _______grasshopper (imagen extraída de

These insects are also called Exopterygota (from Latin exo- = “outside” + pteron = “wings”), because in these organisms the wings are progressively and visibly formed at the outside part of their body.

Holometabolous metamorphosis

In general terms, it’s considered the most radical metamorphosis in insects and also probably the most well known transformation by all of us. The most famous example is the one performed by lepidopterans (butterflies and moths); but there are also more insects that are holometabolous, such as coleopterans (beetles), hymenopterans (bees, wasps and ants) and dipterans (flies and mosquitoes).

In the complex, complete or holometabolous metamorphosis, insects are born as larvae, that is, a premature stage that doesn’t resemble anatomically nor physiologically to the adult. In addition, they don’t share feed sources nor habitat, as it is the case of hemimetabolous organisms. As in hemimetabolous insects, these larvae go through successive molts until reaching the size enough to undergo the metamorphosis, when they perform their last molt.

Beetle larva (“Curl grub” by Toby Hudson – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons).

After their last larval stage, larvae enter in a stage of inactivity, moment they stop feeding and remain motionless. This stage is known as pupal stage (when they become a pupa or a chrysalis in butterflies). Usually, larvae begin to resemble to the adults at the end of this stage due to the anatomical modifications that take place and also to the appearance of new organs and tissues.

Pupal stage of Cetonia aurata (Coleoptera) (“Cetoine global” by Didier Descouens – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons)

Once the transformation process ends, the organisms leave that motionless state and acquire their adult form that has wings and is totally mature.

In summary, the scheme of this process could be:

Holometabolous development of a lepidopteran (Picture from

In contrast with hemimetabolous insects, the appearance of wings in holometabolous organisms takes place inside their body and become visible only at the end of the pupal stage. For this reason, they are also known as Endopterygota (from Latin endo-= “inside” + pteron=”wings”).

Origin and function of insect metamorphosis

Origin: the fossil record

Insects are, as we discussed in previous articles, one of the animals with greater evolutionary success. Between 40%-60% of all insect species are holometabolous (complete metamorphosis), because of what we deduce that holometabolous metamorphosis was positively selected during the evolution of this group. In fact, fossil records suggest that this kind of metamorphosis appeared only once, so all holometabolous insects derive from the same ancestor.

According to these data, wingless insects or ancient Apterygota and early winged insects were ametabolous. Then, all winged insects started to develop some kind of hemimetabolous metamorphosis during the Carboniferous and the Permian (300 Ma). Finally, the first insects considered as holometabolous appeared during the Permian period (280 Ma).

What could be the reason of this positively selection?

In the latest paragraphs, we talked about the different feeding sources and habitats of both youth and adult. The fact that different life stages of the same animal exploit different resources could prevent the intraespecífic competition (i.e. competition for resources between organisms of the same species). This fact would mean a great advantage for these organisms, so that holometabolous development, which is characterized for being divided in very different stages, could have been more successful than the hemimetabolous or the ametabolous.

Thus, we can say the main functional sense of metamorphosis could be to minimize the intraespecífic competition for resources. But there is still more: the more specialized are the different stages of an insect, the greater would be the chance to exploit more and better the resources. E.g. in parasitic forms, the differences between different stages tend to be huge, because the difficult situations they have to face require a specific specialization in each moment of the life cycle.

Sin título
Larva and adult of Danaus plexippus (monarch butterfly) (sources: larva picture by Victor Korniyenko, Creative Commons; adult picture of public domain).

.        .         .

So, likewise the appearance of wings promoted the expansion and diversification of insects worldwide, the metamorphosis could have acted as a diversifying engine by increasing the capacity to exploit more and better resources.


Main picture by Steve Greer Photography.