The Desert Locust: Swarm Behavior

The desert locust is a native species to the dunes of Morocco. Can its behavior be used and simulated in parametric design to create new types of form?

swarm

The widespread presence of the desert locust is contributing to massive loss in agriculture each year – especially due to the fact that these insects inhabit areas of the world where options for food production are limited. Throughout parts of Asia, the Middle East and North Africa, the behavior of these insects cause a massive negative impact for nearly a tenth of the worlds’ population and have only been possible to control and limit during recent decades. That which is able to cause this destruction is an attribute that other types of grasshoppers lack – the ability to form swarms.

locust

The behavior during its life cycle differs in two stages. Either during the solitary (young) phase or gregarious (adult) phase, locusts form groups containing everything from a couple of thousands, up to several billions of individuals, with swarms covering up to 1200 square kilometers.

As a young, undeveloped species, it forms wandering bands that stick to certain daily routines. These routines are more or less regular patterns. During nights and early mornings groups are found to rest on plants, bushes and stones, off from the ground. Marches happen during the greater part of the day. They feed on low vegetation or on plants used for resting. Change in size and splitting of bands happens by too great numbers in one band, differences in age of individuals or due to environmental factors, such as availability of food or difference in temperatures.

band

As adults, the locusts develop wings. Thus, the size of groups tend to enlarge to massive swarms and the possibility to relocate and feed is increased. The swarms can contain billions of locusts and can eat roughly their own size of weight per day.

swarm-2

This massive movement requires cohesion and a set of rules taught by instinct to direct the swarm. Even though no central command exists and individual movement roughly is decided by the rule to follow your neighbor, a swarm can displace the distance as far as from Africa to the Caribbean.

Locust swarms have the same basic instincts as swarms of any other species, so because it is easy to gather all these basic behavioral patterns, computer software has been developed to imitate swarms by some steps. The three mechanics to mimic the behavior are quite simple and apply to an individual;

  • Separation – Steer to avoid crowding local flockmates
  • Alignment – Steer toward the average heading of local flockmates
  • Cohesion – Steer to move toward the average position of local flockmates

basic-rules

These rules give a basic understanding of the instincts of locusts and other animals (primarily birds) and were first introduced in the software program Boids in 1986. In addition to these rules, other factors can be added.

boids

To translate this into modern architecture, programs such as grasshopper with plug-ins can be used. If rules that are brought over from Boids can be applied, as well as factors that the insect faces in nature are added, a realistic simulation of swarming can be created. This creates a random movement of a collection of so called agents (individuals) that follows a set of rules. This parametric process will mainly help to create form, and in lesser extent function. Just like a young or adult group of locusts, the process can create patterns in form of 2D (band behavior) or form in 3D (swarm behavior) within rules that take aspects like physical barriers, evolving of agent groups and temperature in consideration. The result will end in very organic shaped architecture, emerged by the path of the agents. By using techniques such as 3D-printing and CNC-milling, complex prototypes, patterns and models can be created.

3d

The development will likely change into expanding the rules and aspects in addition to adding new ones, to proceed past the original idea of swarm behavior, to simulate other flows, like water, wind or sand, which can later also be implemented in the final project.

The challenges of the idea will most probably be defining the rules in grasshopper. After this step, there will be a question of how much to alter and how much to leave to chance. In any case, simulating swarm behavior in a frame of rules will generate many opportunities to create form in a new way.

By Viktor Tamm

 

References:

Biological control of locusts. FAO Newsroom. 2006

http://www.fao.org/newsroom/en/focus/2006/1000345/

What are locusts? Humanity Development Library 2.0.

http://www.nzdl.org/gsdlmod?e=d-00000-00—off-0hdl–00-0—-0-10-0—0—0direct-10—4——-0-1l–11-en-50—20-about—00-0-1-00-0-0-11-1-0utfZz-8-10-0-0-11-10-0utfZz-8-00&a=d&c=hdl&cl=CL1.10&d=HASHd1edbf77fbe3fa2e5e3da5.3

Desert Locust-Schistocerca gregaria. Humanity Development Library 2.0

http://www.nzdl.org/gsdlmod?e=d-00000-00—off-0hdl–00-0—-0-10-0—0—0direct-10—4——-0-1l–11-en-50—20-about—00-0-1-00-0-0-11-1-0utfZz-8-10-0-0-11-10-0utfZz-8-00&a=d&c=hdl&cl=CL1.10&d=HASHd1edbf77fbe3fa2e5e3da5.4

Craig Reynolds. Background and update. Boids. 2001

http://www.red3d.com/cwr/boids/

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