This article presents a review of the current state of the art in the study of human consumption of insects in the Amazon basin and, in particular, of the larva of the beetle Rhynchophorus palmarum which is the insect of greatest consumption by the native indigenous communities of the Amazon basin. It includes detailed information on cultivation, collection and consumption, as well as the dietary, medicinal and symbolic role the Rhynchophorus plays in a variety of Amazonian cultures. The article emphasizes aspects related to its role as vector of a plague that damages commercial agriculture of palms and some fruit trees, as opposed to its role as a food source that constitutes a rich source of protein of high biological value.
- edible insects
- Amazonian protein
- insect’s nutritional value
- Rhynchophorus palmarum
- Amazonian indigenous diet
Insects have attracted the attention of mankind since ancient times for both negative and positive reasons. Negative, related to their destructive effects on agricultural and industrial crops, causing large economic losses, and their harmful effects on human health, causing huge human losses by transmitting diseases such as Chagas disease, dengue, malaria, yellow fever, chikungunya, leishmaniasis and others. Positive, related to their use as a human food source, of particular importance to help mitigate, in the medium term, critical cases of food insecurity and famine, and feeding other animal organisms . Insects play a key role as regulatory elements of terrestrial ecosystems, fundamental in pollination processes, important as predictors and bioindicators of environmental changes  and to evaluate the impacts of fragmentation of plant cover, fire and invasive plants [3, 4]. Insects are also used as bioindicators of plant stress , elements to enrich the soil , accelerate the recycling of detritus  and for the biological control of pests [2, 8, 9]. In many cultures they are useful as effective popular medicines [10, 11, 12, 13, 14], and cutting edge medical technology . Insects are highly valued, in many parts of the world, as symbols in religious rituals and in other cultural practices [16, 17, 18, 19, 20, 21].
The importance of insects is remarkable from a multidimensional perspective related to human culture , and especially in relation with biodiversity. Insects represent the animal group with the most evolutionary success . They also constitute the largest animal biomass on the planet , with a higher volume than the rest of the animals together (, pp. 67–68). Insects have the advantages of abundance (wide geographical distribution and great adaptability), productive facility (high reproduction rate, easy handling and cultivation, efficiency in food conversion and great potential for internal and external commercialization) [13, 24, 25, 26], and a high nutritional value suitable for human and animal uses [13, 25, 27, 28, 29, 30, 31]. Insects are, for these reasons, an excellent food alternative for a world with a growing human population, which lives in a scenario characterized by an inequitable distribution of productive land, employment and income, and which faces serious problems in accessing enough quality food for expanding populations [11, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41].
Around the world, more than 1 million species of insects have been described by science, while the existence of 5–10 million more is estimated, yet to be described , which makes them the group of animals of the greatest diversity on the planet. Of the total described, there are, according to the most conservative estimates, between 1900 [37, 43] and 2000 species of insects , used as food by nearly 3000 ethnic groups in more than 102 countries [11, 24].
Considering the relationship between the number of edible insect species with respect to the total number of insect species, we find that only 0.2% of the described species are edible, which represents just 0.033% of the total estimate of insect species, described or not. Of the total number of insects, nearly 60,000 described species live in the Amazon basin. There, the proportion of edible insect species, estimated at about 135 species, gives a figure of 0.00225% with respect to the total of regional insect species. This means that the percentage of edible insect species in the world is negligible (0.2%, of the total described, and 0.033% of the estimated total), and even more so in the case of the Amazon (0.00225%).
When examining the taxonomic concentration of the insect species described and, in particular, edible insects, we find that, approximately, 74%corresponds to four orders:
When taking into account the fidelity level of insect consumption in the Amazon basin, i.e., the frequency of their use as a dietary component, it is observed that only 30 species of insects are frequently consumed, highlighting, among them, the consumption of
The objective of this article is to review the double impact of the larva of
To collect the information needed for this research, which is part of a larger investigation, two methods were used. First, the method of in situ observation, carried out directly in a number of native indigenous communities of the Peruvian Amazon, supplemented by informal interviews with members of these communities, particularly those located near the cities of Iquitos and Nauta, in the Loreto region, during the period from May to July 2015. Several popular regional markets were visited, and especially the large market of Bethlehem, to interview small traders, some informal, who regularly offered products derived from about 20 varieties of Amazon palms (parts of the plant: drupe, palmetto or inflorescence of the bud, and related insects). This field work included an excursion for the collection of edible insects (in particular Suri,
The second method consisted of a neat bibliographic-bibliographical review carried out in two specialized libraries located in the cities of Iquitos: the rich library of the Institute of Amazonian Studies of the Peruvian Amazon (IIAP) and the beautiful library of the Center for Theological Studies of the Amazon (CETA) In addition, information was collected over several months in libraries in Lima, particularly the one from the French Institute of Andean Studies (IFEA) and the Institute of Peruvian Studies (IEP). During that time we also interviewed personalities linked to different aspects of Amazonian life: the historian and novelist Róger Rumrrill, the journalist and novelist Juan Ochoa-López, the chefs Pedro Miguel Schiaffino and Pilar Agnini and the anthropologist Alberto Chirif, one of the greatest experts and analysts of the Peruvian Amazon from the perspective of the social sciences.
The approach to the subject of the investigation can be considered in three parts. In the first we describe the
3.1 Description of the
Rpand its larval stage (form)
It is a matt black beetle, with a size that varies between 2 and 5 cm. In adult state, this coleopter presents sexual diformism, that is, the male is different from the female. The female has the beak curved and smooth, and longer than that of the male. The male is easily recognized because, in addition, he carries a tuft of mushrooms in the dorsal part of the beak. Both male and female show activity both in the day and in the night: they are observed in the fallen trunks of the palms during the early hours of the morning or at the end of the afternoon, although they are more active towards 11 o’clock at night ([55, 56, 57], pp. 11–13).
The female lays her cream white eggs, of a size that fluctuates between 1.0 and 2.5 mm, in palm trunks. It deposits them, in an average of 900 units, in vertical position on the soft tissue of the open trunk of the palm, protecting it with a brown waxy substance. After 2–4 days, the larvae emerge, without legs and with a body length of a little more than 3 mm, slightly curved in the belly. From there it begins its development in nine instars, which last between 42 and 62 days, until it reaches instar IX, when it becomes a pupa. It then takes 30–45 days for the adult to emerge, and from 7 to 11 days to leave the cocoon [55, 58].
The females oviposit in the cuts of the petiolar bases of the palms with wounds or rot. There, inside the infected palm, usually near the rotting bud, the insect develops, fulfilling its total life cycle until reaching its final form (, p. 21), depending on the material or substrate on which it feeds (colonized substrate). The life cycle ranges from 119 to 231 days, when they are raised in the laboratory , and under normal conditions, a minimum of 122 days: 3.5 days as eggs, 60.5 days as larvae, 16 days as a nymph and 42 days as an adult [24, 60, 61]. The females have an oviposition period of up to 43 days. A female can oviposit up to 63 eggs in a day, and from 697 to 924 during her entire cycle [55, 62, 63, 64]. In the final instar, the larva has a length of 5–6 cm, and a weight of 12–30 g .
Rpas a plague
In the case of the Amazon basin, the larvae of the
Some researchers several decades ago posed the need to value the consumption of insects as an excellent food resource, widely used among Amazonian Indians, among Mexican rural dwellers and in many Asian and African cultures. These authors [15, 72] considered that protein malnutrition among indigenous groups in the Amazon was relatively low in the area due to its high consumption of insects, fungi, drupes and almonds. That opinion, perhaps a bit exaggerated, can be sustained with some reservations. Riparian natives satisfy their protein needs basically with the consumption of fish. Some riparian groups have an average per capita consumption of 20–50 kg per year, although in some communities they reach consumption levels close to 200 kg per year. In these conditions, the consumption of insects plays a secondary role, complementing the diet, not as a primary component but as a necessary complement.
Just as insect consumption has been overestimated in some studies, so in others such consumption has been underestimated. Many times indigenous people do not recognize this consumption in the food consumption surveys that are applied to them. The Indians in the most advanced process of cultural assimilation do not declare that consumption because they have learned in the cities that this consumption is considered unpleasant and dirty. This concealment does not occur with indigenous groups that are proud of their ethnic identity and boast of such a food practice.
Although not declared openly, the consumption of insects is common throughout the Amazon basin. That is evident if one makes a visit to any indigenous community. In some native communities of the Loreto region, in the Peruvian Amazon, we directly recorded the consumption of nine species of insects belonging to several orders, although the most consumed was the
Depending on the season, and rising or falling river levels, which changes the availability of food in the jungle by affecting the relative productivity of hunting and fishing, recollection is used to augment these primary sources. This activity includes wild fruits, drupes of palm trees, fungi, mollusks, small terrestrial animals such as amphibians, and edible insects. The consumption of these insects is very important during some times of the year. Paoletti et al. , based on studies by Ramos-Elourdoy and Viejo Montesinos , using various sources, recorded much higher consumption among the Yanomami, an indigenous group that inhabits the Venezuela-Brazil border, during particular seasons.
The nutritional value of edible insects is sufficiently proven by numerous laboratory studies. The protein content of edible insects varies between 30 and 40%: from 30% for wood larva to 80% in the wasp
The protein of animal origin is important for its high biological value, which depends on the number and variety of essential amino acids in its content, and its digestibility or ease of assimilation by the human body. The biological value of the protein corresponds to the proportion of protein absorbed and used by the organism. To be used most efficiently, protein is required to have all the essential amino acids in the right proportions. This happens with foods of animal origin such as milk and meat. The protein of edible insects is also of high biological value, similar to that of meats, with a triple advantage over them: it has a lower relative price, is easier to digest and is healthier because it does not have cholesterol . In addition, if a protein of high biological value, such as insects or meat, is consumed and combined with another of lower biological value, such as cassava or plantain, the foods complement each other, and the biological value of the resulting dishes increases. However, the consumption of insects’ greatest importance for the conservation of the environment lies in the fact that it has a better efficiency index for the conversion of food into biomass.
The value of an animal as a source of nutrients depends mainly on its nutritional contribution and on the efficiency with which this animal converts the food consumed into biomass [75, 80]. In this respect, the animal that gains the most weight for each gram of food consumed is more efficient. To obtain 1 kg of beef, 13 kg of food is needed. For chicken, the most efficient among the commonly consumed animals, 6 kg is required. On the other hand, only 2 kg are needed for insects, showing a high rate of conversion efficiency. For Costa-Neto  and Krajick , insects are more efficient in relative terms than other animals, because they are invertebrate, cold-blooded animals. The disadvantage they present is that their consumption is seasonal and their production is not currently significant in terms of volume sufficient to supply the potential market. This situation can be reversed, and we are beginning to see large-scale cultivation in some countries of the world, such as Thailand, Mexico and Spain.
Recollection of insects is an activity carried out by the far majority of Amazonian indigenous communities. To analyze its cultural dynamics and dietary contribution, it is necessary to understand the changes produced in the larva. The timing of the
When human action intervenes, the collecting activity goes much further, becoming in practice a work of cultivation or protoculture, as Ramos-Elourdoy and Viejo Montesinos  called it. In this case, the indigenous person fells the palm, and in the downed trunk makes an incision approximately 10 cm × 10 cm, leaving a mark to identify the place. Two months later he or she returns to the site, knowing what to look for and where to look . The collector comes back this time with an ax and a container to collect the larvae. He or she then opens the bark of the trunk with the ax, and extracts 30–40 larvae each time, part of the harvest of a day. A whole palm tree can produce over 500 larvae. Then, the collector takes the larvae home to consume with the family. The period of greatest collection goes, in the Peruvian Amazon, from July to October, both in the Lower and Upper Amazonian basin. Depending on the season, the identity of the collectors changes. If it is a hunting or fishing season, and men are absent from the community, women and children are responsible for the collection.
The “cultivation” or “proto-culture” of
Neto and Ramos-Elourdoy (, p. 430) point out that the collection of edible insects depends on four factors: food restrictions and taboos, traditional customs, personal taste or taste preference of the group and the search for food security to guarantee survival. Another factor could be added: seasonality, because in the rainy season the process of insect infestation is accelerated. These authors also argue, together with Miller , that the use of an insect as food is related to four variables: the environment, the availability and accessibility of insects, the mode of production and the forms of reproduction of the insect and culture and food restrictions. In several native communities the collection and cultivation of insects corresponds to indigenous women and children, and they exhibit a festive spirit while accomplishing this task, which they perform even in times of abundance of hunting and fishing products.
Rpas a symbol
It is known that when consuming food, symbols, meanings, and signifiers are consumed at the same time. In such a way, the consumption of insects goes beyond obtaining nutrients in moments of scarcity or to supply deficiencies of proteins and fats. Every food substance must be viewed from a three-dimensional perspective, because it provides, at the same time, nutrients, medicines and symbols. The consumption of insects in the different regions of the Amazon basin is inscribed within a culture, whose members use symbols to communicate, as individuals and as a social entity, and to express them and think about their culture. Foods contain messages or stories that serve, along with other cultural elements, to insert themselves into the worldview or matrix of a culture. These messages are transmitted inter-generationally and incorporated, with adjustments, into the dietary patterns of a social group . An excellent illustration of the symbolic consumption of insects is the study carried out by Acuña-Cors  in an indigenous community of the Reyes Metzantla, in Puebla, Mexico. Also notable are the mentions made by Macera and Casanto (, p. 242) of the symbolism associated with the suri larva (
The symbolism of insect consumption is different when it occurs among non-Amazon urban consumers. In this context, the edible insect leaves everyday life to become an exotic matter that, in some cases, produces amazement, and can become an object of consumption and gastronomic tourism. However, in most cases consumption of insect is viewed with horror by visitors from other cultures, who consider insects dirty, disease-ridden pests, and which arouses feelings of apprehension and disgust, which can even cause phobias and neuroses and even physical illness.
The subject of edible insects has been attractive for popular magazines, but not as much for scientific research. Even in Latin America, where insects are consumed in almost all countries, there are still a lot of reservations about the matter, as if it were an exotic food practice exclusive to the most backward and unimportant indigenous communities. There have been few researchers who address this area of study, the exceptions being mostly European and American investigators. Among Latin Americans, researchers from Brazil and Mexico stand out, and some have made great contributions in the field . Most of the studies done in Mexico are devoted to the study of insects grouped in
On the symbolic aspects of the consumption of insects, and the comparative cultural representations between the different ethnic groups of Central America and Mexico, as well as of South America, there is much work to do. Little research has been done on insect consumption between the populations of the Caribbean islands and black African-American populations. The elaboration of didactic manuals is necessary to develop popular enterprises related to the “cultivation” of edible insects. The specialists in the culinary arts must write recipes that introduce novel ways to facilitate the consumption of insects, overcoming the reservations that people have concerning their consumption. On the subject, only entomologists, ethnozoologists and applied anthropologists have been concerned thus far, but not nutritionists, for whom it should be a major concern. They, and various health organization, have the difficult task of developing efficient campaigns, attractive from the point of view of “taste”, to promote the consumption of insects of high nutritional value, as an effective tool in reducing the serious problems of chronic malnutrition that affects a large percentage of the child population of developing world, constituting a situation of food insecurity that impacts the political, socioeconomic and public health realities in these countries. This study tries, at a minimum, to be a critical revision of the current state of the art around this topic, but it leaves many unanswered questions that must be approached by other investigators interested in the subject.
Edible insects represent an important source of protein and fats in the diet of the indigenous Amazonian population, particularly during times when the availability of products derived from hunting and fishing is reduced, these being the main and usual sources of necessary proteins. The protein derived from insects is of high biological value, due to its excellent content of essential amino acids, both in variety and quantity. It also results in easy digestibility, a relatively low energy cost and a high efficiency index in feed/biomass conversion. These attributes make the consumption of edible insects an attractive alternative that could be used, in the medium term, to tackle the serious problems of chronic malnutrition worldwide, if the adequate measures were taken to promote its large-scale production and consumption.
Despite its abundance and importance in the diet of indigenous people of the Amazon, as an alternative source of protein and fats, the